LESSON XL.
846. Why does a mouse, painted upon one side of a card, and a trap upon the other, represent to the eye a mouse in a trap when the card is rapidly twirled upon a string?
Because the image of the mouse is brought to the retina of the eye before the image of the trap has passed away. The two impressions, therefore, unite upon the retina, and produce the image of a mouse in a trap.
"Honour thy father and thy mother * * That it may be well with thee, and thou mayest be long on the earth."—Ephesians vi.
Fig. 36.—CARD WITH MOUSE-TRAP.
Fig. 37.—REVERSE OF CARD WITH MOUSE.
847. Why will a bow stretched out of its natural position, propel an arrow through the air?
Because its substance, being highly elastic, the particles thereof seek to restore themselves to their former state, as soon as the resisting power is withdrawn. The force derived from this elasticity, is communicated to the arrow by the string against which it is placed.
848. Why is the arrow propelled forward?
Because the elasticity of the bow, acting equally upon its two ends, to which the string is fastened, produce a line of force in a diagonal direction. It thus illustrates the law, that when a body is acted upon by two forces at the same time, whose directions are inclined to each other, it will not follow either of them, but will describe a line between the two.
849. What forces tend to arrest the flight of the arrow?
The friction of the air, and the attraction of gravitation.
"My son, give, I pray thee, glory to the Lord God of Israel, and make confession unto him."—Joshua vii.
850. Why are feathers usually fastened to the ends of arrows?
Because the greater friction of air acting upon them, opposes the progress of that part of the arrow in a greater degree than it does the other portion. The effect is, to keep the point of the arrow forward, and in a straight line with its opposite extremity. If the arrow were shot the reverse way from the bow, it would turn round, in the course of its flight, in consequence of the friction of the air, offering greater resistance to the progress of the feathered end.
Fig. 38.—BOW AND ARROW.
Fig. 39.—JEW'S HARP.
851. Why does a Jew's harp give musical sounds?
Because the vibrations of the metal tongue are communicated to the ear.
852. Why will not the Jew's harp produce loud sounds unless it is applied to the mouth?
Because the vibrations are not very intense, but when it is blown upon by the breath, the air is pressed upon it, and the vibrations are thereby rendered more powerful.
853. Why does the alteration of the arrangement of the mouth, affect the formation of the sounds?
Because it sends the air to the tongue of the harp in a greater or lesser degree of compression.
"Hear, ye children, the instruction of a father, and attend to know understanding."—Proverbs iv.
854. Why does the pressure applied to the handle of an air pistol propel the cork?
Because, between the cork A and the air-tight piston C, there is a closed chamber of air b. When the handle D, which moves the piston C, is rapidly pushed in, it compresses the air until it is so much condensed, that it forces out the cork A.
Fig. 40.—AIR PISTOL, OR "POP-GUN."
855. Why must the handle be drawn out, before the cork is placed in?
Because otherwise a partial vacuum would be formed between A and C, and there would not be sufficient air to force out the cork by the return of the piston C D.
856. Why does water rise in a syringe when the handle is drawn out?
Because the pressure of the air on the water outside of the syringe, forces it into the space vacated by the drawing up of the handle, and where, otherwise, a vacuum would be formed.
Fig. 41.—SYRINGE, WITH JET OF WATER.
857. Why does not the water run out when the syringe is raised?
Because the pressure of the air upon the small orifice resists the weight of the water.
858. Why does the water leak out, but not run?
Because water has a tendency always to move to the lowest point, but as the air does not enter freely the water cannot escape. It therefore drops, as small portions of the air enter.
"Remember now thy creator in the days of thy youth."—Ecclesiastes xi.
859. Why cannot the handle be pressed in, if the finger is applied to the orifice?
Because water is not compressible, like air; it must therefore escape before the handle can be pressed in. Air may be forced into a much smaller compass than is natural to it; but it is impossible to compress water in any great degree.
Fig. 42.—"SUCKER."
Fig. 43.—HOOP.
860. Why does a "sucker" raise a stone?
Because underneath the sucker a vacuum is formed and the external air, pressing on all sides against the vacuum, lifts the stone. The term "sucker" is founded upon the mistaken notion that the leather "sucks," or "draws" the stone. That such is not the case is evident: if, when the stone is suspended, a pin's point be passed under the leather, so as to open a small passage for the air, the stone will drop instantly.
861. Why does a hoop roll, without falling to the ground?
Because the centrifugal force gives it a motion which is called the tangent to a circle—that is, a tendency in all its parts to fly off in a straight line. When a piece of clay adhering to the hoop flies off, it leaves the hoop in a line which is straight with the part of the surface from which it was propelled; this line is the tangent to the circle of the hoop; and the tendency of all the parts of the hoop to fly off in this manner, counteracts the attraction of the earth, so long as the hoop is kept in motion.
"Children obey your parents in all things: for this is well-pleasing unto the Lord."—Colossians iii.
862. Why does the hoop, in falling, make several side revolutions?
Because its onward movement, not being quite expended, influences the centre of gravity of the hoop, and changes its line of direction. The hoop is also elastic, and when its sides strike the earth, they spring up again, and continue turning until the opposing forces are overcome by the attraction of gravitation.
863. Why will a little boy balance a large boy on a see-saw?
Because the "see-saw" may be placed so that its ends are at unequal distances from the centre. This gives the little boy the power of leverage, by which is meant the increase of power, or weight, by mechanical means.
Fig. 44.—BOYS AND "SEE-SAW."
864. Why does the little boy sink to the ground when the larger boy slightly kicks the earth?
Because the larger boy, by kicking against the earth, opposes by mechanical force the attraction of gravitation acting upon him, and he becomes temporarily less attracted to the earth than the little boy.
"Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous."—1 John iii.
865. Why can the little boy, if he choose, keep the big boy up, when once he is up?
Because, as the big boy is then on an inclined plane with the fulcrum, or centre upon which the see-saw moves, the arm of the lever, upon which the big boy sits, is relatively shortened, and he has then less mechanical power. Also, a portion of the weight of the larger boy is transmitted along the lever to the arm upon which the little boy sits.
Fig. 45.—TRAP AND BALL.
866. Why is the ball propelled upward, in the game of trap and ball, when the trigger is struck?
Because, when the trigger is struck at A, it is forced downwards, turning upon the fulcrum B, the opposite end, forming the spoon, is thereby forced upwards, describing a small arc, or curved line; but directly the ball is set free from the spoon, it rises in a right line with the direction it was taking, at the moment it was set free.
Fig. 46.—BAT AND BALL.
867. What principles of natural philosophy are illustrated by the results of bat and ball?
Percussion, when the bat strikes the ball; rotatory motion, when the ball is sent whirling away; momentum, which it acquires by velocity; elasticity, when it rebounds from an object against which it strikes; reflected motion, when it is turned by a body upon which it impinges; friction, as it rolls along the ground; the communication of force, when it sets another body in motion against which it strikes; gravitation, when it falls to the earth; and inertia, when it lies in a state of rest.
"A wise son makes a glad father: but a foolish son is the heaviness of his mother."—Proverbs x.
868. Why do pith-tumblers always pitch upon one end?
Fig. 47. PITH-TUMBLER.
Because the lead B is specifically heavier than the pith to which it is attached; it therefore always falls undermost; and as the lead is rounded off, just like the spill of a top, after the head has oscillated a little, and expended the force of the momentum of its fall, it will settle upon its centre of gravity, or the point through which it is attracted to the earth.
869. Why do the figures upon the "Thaumatrope" appear to dance, when they are made to revolve before a mirror?
Because the eye, in looking through the holes in the card, towards the reflections in the mirror, receives a rapid succession of impressions. As the figures upon the card are represented in a graduated series of positions—the first one standing upright, the second with his knees a little bent, the third a little more bent, as in the act of springing, and so on, the figure being in each case the same, but the position slightly altered, imparts an impression to the mind, through the eye, that one figure is passing through a series of motions.
Thaumatrope.—From two Greek words, meaning wonder and to turn.
We have said enough, we hope, to show that even the play-hours of children may be made instructive to them; and that the simplest toys may be used to illustrate some of the grandest laws of nature. Nor may this kind of instruction be confined to children alone. Grown-up people, whether participators in the sports of youth, or simple observers of their games, may gain instruction for themselves, and be the better teachers of their children, by taking an interest in their enjoyments, and giving to their minds, through the attractiveness of pastime, a taste for observing and estimating the varied phenomena which present themselves.
Moreover, we think that parental government acquires a greater power when it leans towards the natural desires of childhood, and wins those desires into a proper direction. Love existing between parent and child is the best tie to home, and the strongest incentive to duty. There is also something in the gentleness of childish nature which may influence for good the sterner mould of man, too often warped and clouded by the cares of life.
Jesus said, Suffer little children, and forbid them not, to come unto me; for of such is the kingdom of heaven."—Matthew xix.
Fig. 48.—THAUMATROPE, OR "WONDER-TURNER."
In Kay's "Life of Sir John Malcolm," we find an admirable and apt passage. Sir John says:—"I have been employed these last few hours with John Elliot, and other boys, in trying how long we could keep up two cricket-balls. Lord Minto caught us. He says he must send me on a commission to some very young monarch, for that I shall never have the gravity of an ambassador for a prince turned of twelve. He, however, added the well-known and admirable story of Henry IV. of France, who, when caught on all fours carrying one of his children, by the Spanish envoy, looked up and said, 'Is your excellency married?' 'I am, and have a family,' was the reply. 'Well, then,' said the monarch, 'I am satisfied, and shall take another turn round the room,' and off he galloped, with his son on his back flogging and spurring him. I have sometimes thought of breaking myself of what are termed boyish habits; but reflection has satisfied me that it would be very foolish, and that I should esteem it a blessing that I can find amusement in everything, from tossing a cricket-ball, to negotiating a treaty with the Emperor of China. Men who will give themselves entirely to business, and despise (which is the term) trifles, are very able, in their general conception of the great outlines of a plan, but they feel a want of knowledge, which is only to be gained by mixing with all classes in the world, when they come to those lesser points upon which its successful execution may depend."
"Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God."—Corinth. x.
CHAPTER XLI.
Because the atoms of which our bodies are composed are continually changing. Those atoms that have fulfilled the purposes of nature are removed from the system, and, therefore, new matter must be introduced to supply their place.
870. Why do we eat animal and vegetable food?
Because their substances are composed of oxygen, hydrogen, carbon, and nitrogen—the four chemical elements of which the human system is formed. They are, therefore, capable of nourishing the body, after undergoing digestion.
871. Why do we masticate our food?
Because mastication is the first process towards the digestion of food. Before animal or vegetable substances can nourish us, their condition must be entirely changed, their organic states must be dissolved, and they must become simple matter, in a homogeneous mass, consisting of the four chemical elements necessary to nutrition, and they must again be restored to an organic condition.
872. Why does saliva enter the mouth when we are eating?
Because, in addition to the mechanical grinding of the food by the action of the teeth, it is necessary that it should undergo certain chemical modifications to adapt it to our use. There are placed, therefore, in various parts of the body, glands, which secrete peculiar fluids, that have a chemical influence upon the food.
The first of these glands are the salivary glands of the mouth, which pour out a clear watery fluid upon the food we eat, and which fluid has been found to possess a property which contributes to the digestion of food.
The moisture afforded by the salivary secretion is also necessary to enable us to swallow the food.
"And the Lord said unto him, Who hath made man's mouth? or who maketh the dumb, or the seeing, or the blind? have not I the Lord?"—Exodus iv.
873. Why does the salivary juice enter the mouth just at the moment that we are eating?
Because the glands, which are buried in the muscles of the mouth, and which in their form are much like bunches of currants, are always full of salivary secretion. There are nerves which are distributed from the brain to these glands, and when other nerves which belong to the senses of taste, of sight, or of feeling, are excited by the presence of food, a stimulus is imparted to the salivary glands, through the nerves that surround them, their cells collapse, and the juice which they contain is poured out through their stems, or ducts, into the mouth.
874. How do we know that impressions imparted to one set of nerves, may be imparted to another set, so as to put any particular organ in action.
Because very frequently the mere sight of rich fruit, or acid substances, will cause the saliva to flow freely. In this case it is evident that the salivary glands could not see or know that such substances were present. An impression must, therefore, be made upon the brain, through the organ of vision, and the desire to taste the substances being awakened, a nervous stimulus is imparted to the glands of the mouth, and they at once commence their action, as if food were present.
875. Why does food descend into the stomach?
Because, after the teeth, the tongue, and the muscles of the mouth generally, have rolled the food into a soft bolus, it is conveyed to the back of the mouth, where it is set upon the opening of the throat (œsophagus). It does not then descend through the throat by its own gravity, because the throat is generally in a compressed or collapsed state, like an empty tube; and we know that persons can eat or drink when with their heads downwards. The œsophagus is formed of a number of muscular threads, or rings, and each little thread is like a hand ready to grasp at the morsel that is coming. As soon as the bolus is presented at the top of the throat, these little muscular hands lay hold of it, and transmit it downward, passing it from one to another, until it is conveyed through the long passage, to the door of the stomach, which it enters.
"Remove far from me poverty and lies; give me neither poverty nor riches; feed me with food convenient for me."—Proverbs xxx.
Fig. 49.—SECTION OF THE STOMACH, &c.
A. The inner coat of the stomach. (The stomach is here represented cut through its length, so that we can see its inside.)
B. The lower extremity of the throat, or œsophagus, through which food enters the stomach.
C. The passage out of the stomach, called the pylorus, where a muscular contraction prevents the escape of undigested food.
D. The duodenum, and the ducts through which the bile and pancreatic juices enter and mingle with our food.
876. Why do we not feel the food being transmitted through the throat?
Because the nerves of the body differ in their powers: some are nerves of feeling, some of motion, and others are nerves of the senses. The nerves of feeling are most abundantly distributed to those parts where feeling is most useful and necessary to us. But the faculty of feeling our food undergoing digestion would be no service to us whatever; therefore the nerves of motion are plentifully distributed to the throat and stomach, but very few of the nerves of feeling—just as many as will tell us when we eat anything too hot, or too cold, or that the stomach is out of order.
877. Why do we feel uneasy after eating to excess?
Because the stomach is distended, and presses upon the other organs by which it is surrounded.
"Who satisfieth thy mouth with good things; so that thy youth is renewed like the eagles."—Psalm ciii.
878. Why do we feel drowsy after eating heartily?
Because, while the stomach is in action, a great proportion of the blood of the body is drawn towards it, and as the blood is withdrawn from the other parts of the body, they fall into a state of languor.
879. Why does blood flow more freely to the stomach during digestion?
Because the energy of an organ is increased by the flow of blood, which supplies the material of which our organs are composed, and in which the vital essence, supporting life, resides.
880. Why does excess in eating bring on indigestion?
Because the power of the stomach to digest food is governed by the amount of food required by the system. It seems to be an instinct of the stomach to hold back food which is in excess, and by indications of pain and disturbance to warn its master that excess has been committed.
881. Why is food digested in the stomach?
Because it enters the stomach in the form of a paste, produced by the action of the mouth; and directly food enters, the gastric juice, which is formed by glands embedded in the coats of the stomach, trickles down its sides. This is a more powerful solvent than the salivary juice—it is like the same kind of fluid, only much stronger, and it soon turns the food from a rough and crude paste into a greyish cream (chyme). The heat of the stomach assists the operation, and the muscular threads of the coats move the cream along, in the same manner that the muscles of the œsophagus brought down the food.
The cream is passed towards the door which leads outward from the stomach (pylorus); but if, in the midst of the cream, there are any undissolved particles of food, it closes upon them, and they return again to the stomach to be further changed.
"When thou hast eaten and art full, then thou shalt bless the Lord thy God for the good land which he hath given thee."—Deut. viii.
882. Why does indigestion bring on bilious attacks?
Because the liver secretes a fluid to assist in the digestion of food. The liver is a gland—a similar organ to the glands of the mouth—and it forms bile in the same manner that they form the salivary juice. Only the liver is a much larger gland, and a much greater quantity of blood passes through it. The liver pours its secretion into the biliary duct ([Fig. 49]) to mix with the grey cream as it passes onward, and to further dissolve it. But when the stomach is excited by food which it cannot dissolve, and when the owner of the stomach, disregarding its remonstrances, will persist in over-eating, or in eating things that disagree with the system, then the liver and the stomach sympathise, and the muscular threads, or hands, that prevail all through the alimentary organs, instead of moving onward, move backward, and throw some bile into the stomach to assist to dissolve and remove the excessive or improper food.
![[Fig. 49]](#i-209.jpg){kind=link}
CHAPTER XLII.
883. Why does some portion of the food we eat nourish the system, while other portions are useless?
Because most food contains some particles that are indigestible, or that, if digested, are innutritious, and not necessary for the system. The liver is the organ by whose secretion the useful is separated from the useless; for when the bile enters through the duct ([Fig. 49]) and mixes with the grey cream coming from the stomach, it remains no longer a grey cream, but turns into a mass coloured by bile, having upon its surface little globules of milk, small, but very white. Those minute globules of milk (chyle) are the nutritious particles derived from the food; the other portion, coloured with bile, is the useless residue, or rather the bulk from which the nutrition has been extracted.
"God hath made of one blood all nations of men for to dwell on all the face of the earth."—Acts xvii.
884. Why does the milky, or nutritious matter, separate from the innutritious, upon admixture with bile?
Because the bile contains an oily matter which repels the watery milk of nutrition.
The pancreatic juice also enters through the same duct with the bile. But its precise use is not understood. It is a fluid much like the salivary secretion of the glands of the mouth.
Fig. 50.—GREAT VESSELS OF THE CIRCULATION, AND THE DUCT WHICH CONVEYS NUTRITIVE MATTER TO THE BLOOD.
A B. Jugular veins which return blood from the head to the heart.
C. The superior venæ cava, or trunk vein, which pours the blood returned from the upper part of the system into the heart. There is a similar large vessel which meets this one and brings back blood from the lower part of the body, and they both pour the blood into the right side of the heart.
D E. The branches of the venous system which bring back the blood from the arms.
F F. The great aorta, the blood vessel which conveys arterial blood from the heart, and gives off branches that supply every part of the body.
G. Another large vein which returns the blood from the muscles of the chest, &c.
H H. The thoracic duct, which receives the newly dissolved food from the small absorbents, that collect it from the intestines. It conveys this nutrition (called chyle) upward along the back, until it reaches where the duct turns into the junction of two veins, and pours its contents into the veins bringing blood back to the heart. The nutrition, therefore, is at this moment mixed with the venous blood, and is sent to the lungs to be oxygenised.
"But now hath God set the members in the body, every one as it pleased him."—1 Corinthians xii.
885. How is the nutrition taken away from the bilious residue?
The muscular threads (or hands, as we figuratively call them) continue to push forward the digested matter through a long tube, called the alimentary canal, or bowels. This canal is some thirty feet in length, and is folded in various layers across the abdomen, and tied to the edge of a sort of apron, which is gathered up and fastened to the back-bone. All along this alimentary canal those muscular hands are pushing the digested mass along. But upon the coat or surface of the canal there are millions of little vessels called lacteals, which look out for the minute globules of milk as they pass, and absorb them, which means that they pick them up, and carry them away. There is an immense number of these little vessels, all busily at work picking up food for the system.
Then there is a large vessel, called the thoracic duct, which comes down and communicates with those little vessels (it is a sort of overseer, having a large number of workmen,) and collects the produce of their toil, and carries it upwards to the part where it passes from the organs of digestion into the vessels of circulation.
886. What becomes of the nutrition, when it has entered the vessels of the circulation?
It is sent through a large vein into the heart, entering that organ on the right side, from which the heart propels it into the lungs, mixed with venous blood; and the venous, or blue blood, is sent into the lungs, taking with it the milk, the formation of which we have traced.
887. Why are the venous blood and the chyle sent to the lungs?
Because the venous blood, in its circulation through the body, has parted with its oxygen, and taken up carbon, and it requires to get rid of the carbon, and take up more oxygen. The chyle, also, now combined with the blood, requires oxygen, and having obtained it, is converted into bright red blood, and the blue blood of the veins, having got rid of its carbon, which formed the carbonic acid of the breath, has again become bright red blood. We must therefore, in pursuing our description, cease to speak of blue, or venous blood, and of white milk, or chyle, for the two have now combined, and, with the oxygen of the air, have formed arterial blood.
"My flesh and my heart fainteth; but God is the strength of my heart, and my portion for ever."—Psalm lxxiii.
888. What becomes of the arterial blood thus formed?
It is sent back from the lungs to the right side of the heart, from which it is sent into the great trunk of the aorta, and from thence it passes into smaller blood-vessels, until it finds its way to every part of the system.
Fig. 51.—THE ORGANS OF RESPIRATION.
A. The heart.
B B. The lungs.
C. The aorta, and on either side of the aorta the vessels which convey the venous blood to the lungs to be oxygenised, and the corresponding vessels which return it to the heart, after it has undergone that operation. (For aorta see [Fig. 50].)
![[Fig. 50]](#i-212.jpg){kind=link}
D. The trachea, or large air passage, through which the air passes into the spongy texture of the lungs, when we breathe.
E E. Arteries and veins, being the trunks of the vessels that supply the head, &c.
889. Why does the chest expand when we breathe?
Because the lungs consist of millions of hollow tubes, and cells, which, having been emptied by throwing off carbonic acid gas and nitrogen, become compressed, and the atmospheric air flowing into these millions of spaces, and filling the lungs, just as water fills and swells a sponge, causes them to expand, and occupy greater room.
"All the while my breath is in me, and the spirit of God is in my nostrils. My lips shall not speak wickedness, nor my tongue utter deceit."—Job xxvii.
890. How does the blood communicate with the air in the lungs?
Through the sides of very minute vessels, of which, perhaps, a fine hair gives us the best conception. But these vessels are twisted and wound round each other in such a curious manner, that they form millions of cells, and by being twisted and wound, a much greater surface of air and blood are brought to act upon each other, than could otherwise be accomplished.
891. Why does the blood which is thus formed, impart vitality to the parts to which it is sent?
Because the blood is itself vitalised—is, in fact, alive, and capable of diffusing life and vitality to the organisation of which it forms a part.
This is a very wonderful fact, but no less true than wonderful, that dead matter which, but a little while ago, was being ground by the teeth, softened by the saliva, and solved by the gastric juice and bile, has now acquired life. Nobody can tell the precise stage or moment when it began to live. But somewhere between the stomach and the lungs, melted by the gastric juice, softened by the secretion of the pancreas, separated by the bile of the liver, macerated by the muscular fibres of the bowels, taken up by the absorbents, warmed by the heat of the body, and ærated in the lungs, it has by one, or by all of these processes combined, been changed from the dead to the living state, and now forms part of the vital fluid of the system.
CHAPTER XLIII.
892. Why do we know that the blood has become endowed with vital powers?
Because, in the course of its formation, it has not only undergone change of condition and colour; but, if examined now by the microscope, it will be found to consist of millions of minute cells, or discs, which float in a watery fluid. The paste produced by mastication consisted of a crude admixture of the atoms of food; the cream (chyme) formed from this in the stomach, presents to the microscope a heterogeneous mass of matter, exhibiting no appearance whatever of a new organic arrangement; the milk (chyle) which is formed in the intestines is found to contain a great number of very small molecules, which probably consist of some fatty matter; as the chyle progresses towards the thoracic duct ([Fig. 50]), it appears to contain more of these, and slight indications present themselves of the approach towards a new organic condition.
But wherever vitalisation begins, no human power can say with confidence. Yet there can be no doubt that the blood is both organised and vitalised, and that it consists of corpuscles, or little cells, enclosing matters essential to life.
"But they that wait upon the Lord shall renew their strength; they shall mount up with wings as eagles; they shall run and not be weary; and they shall walk and not faint."—Isaiah xl.
893. Why does the blood circulate?
Because all the bones, muscles, blood-vessels, nerves, glands, cartilages, &c., of which the body is composed, are constantly undergoing a change of substance. It is a condition of their life, health, and strength, that they shall be "renewed," and the blood is the great source of the materials by which the living temple is kept in repair.
894. How is the body renewed by the blood?
Every drop of blood is made up of a large number of corpuscles, each of which contains some of the elements essential to the wants of the system.
Let us, to simplify the subject, consider the blood vessels of the body to be so many canals, on the banks of which a number of inhabitants live, and require constant sustenance. The corpuscles of the blood are the boats which are laden with that sustenance, and when the heart beats, it is a signal for them to start on their journey. Away they go through the arch of the great aorta, and some of the earliest branches which it sends off convey blood to the arms. We will now for a moment dismiss the word artery, and keep up the figure of a system of canals, with a number of towns upon their banks.
"Though hand join in hand, the wicked shall not be unpunished; but the seed of the righteous shall be delivered."—Proverbs xxi.
Well, away go a fleet of boats through the aorta canal, until they reach a point which approaches Shoulder-town; some of the boats pass into the axillary canal and Shoulder-town is supplied; the other boats proceed along the humeral canal until they approach Elbow-town, when another division of the boats pass into other branch canals and supply the wants of the neighbourhood; the others have passed into the ulnar canals and the radial canals until they have approached Wrist-town and Hand-town, which are respectively supplied; and then the two canals have formed a junction across the palm and supplied Palm-town, where they have given off branches and boats to supply the four Finger-towns, and Thumb-town.
Fig. 52.—ILLUSTRATION OF THE SYSTEM OF CANALS THAT SUPPLY THE FORE-ARM WITH BLOOD.
Between A and B the brachial canal, which gives off branches to supply Elbow-town, &c., and then divides into two main courses, diverging to the opposite sides of the arm, and sending a smaller canal down the centre.
D D. The point where the ulnar canal and the radial canal, after having passed and supplied Wrist-town, form a junction, running through Palm-town, and in their course giving off branches to supply the four Finger-towns and Thumb-town.
For further explanations of the engraving, see [57].
![[57]](#i-230.jpg){kind=link}
895. How does the blood return to the lungs, after it has reached the extremities?
The veins constitute a system of vessels corresponding to the arteries. We may say that the arteries form the down canal, and the veins the up canal. The arteries, commencing in the great trunk of the aorta, branch off into large and then into smaller tubes, until they form capillary or hair-like vessels, penetrating everywhere.
"As for man his days are as grass; as a flower of the field so he flourisheth."—Psalm ciii.
The capillary extremities of the arteries, unite with the capillary extremities of the veins, and the blood passes from the one set of vessels into the other. As the arteries become smaller from the point where they receive the blood, so the veins grow larger; the venous capillaries, pour their contents into small vessels, and these again into larger ones, until the great venous trunks are reached, and the blood is passed again into the heart as at first described. ([Fig. 50].)
896. Why do we see blue marks upon our arms and hands?
Because large veins lie underneath the skin, through which the blood of the fingers and hand is conveyed back to the heart.
897. Why are the veins more perceptible than the arteries?
Because the arteries are buried deeper in the flesh, for protection. It would be more dangerous to life to sever by accident an artery than a vein. A person might bleed longer from a vein than from an artery, without endangering life; because the arteries supply the life sustaining blood. The Almighty, therefore, has buried the arteries for safety.
898. Why when we prick the flesh with a needle does it bleed?
Because the capillary arteries and veins are so fine, and are so thickly distributed all over the body, that not even the point of a needle can enter the flesh without penetrating the coats of several of these small vessels.
"Let every thing that hath breath praise the Lord. Praise ye the Lord."—Psalm cl.
899. What occurs during the circulation of the blood?
Not only do the various parts to which the boats are sent take from them whatever they require, but the boats collect all those matters for which those parts have no further use. The bones, the nerves, the muscles, &c., all renew themselves as the boats pass along; and all give something to the boats to bring back. One of the chief exchanges is that of oxygen for carbon, by which a gentle heat is diffused throughout the system. It is for this purpose that fresh air is so constantly necessary.
But other exchanges take place. The blood, in addition to oxygen and carbon, contains hydrogen and nitrogen. But it contains its four elements in various forms of combination, producing the following materials for the use of the body: of 1,000 parts of blood, about 779 are water; 141 are red globules; 69 are albumen; 3 are fibrin; 2 are fatty matter; 6 are various salts.
Albumen and fibrin are a kind of flesh imperfectly formed, and probably are chiefly used in repairing the muscles. The red corpuscles contain the oxygen which goes to combine with the superabundant carbon, and develop heat; the fatty matters probably repair the fatty tissues, and glands that are of a fatty nature; and the various salts contribute to the bones, and to the chemical properties of those secretions which are formed by the glands, &c., while the great proportion of water is employed in cleansing, softening, and cooling the whole, or the living edifice, and it is the medium through which all the nutrition of the body is distributed.
900. Why do we feel the pulse beat?
Because every time that the heart contracts it send a fresh supply of blood to the blood-vessels, and the motion thus imparted creates a general pulsation throughout the system: but it is more distinctly perceived at the pulse, because there a rather large artery lies near to the surface.
"Thy hands have made me and fashioned me: give me understanding, that I may learn thy commandments."—Psalm cxix.
901. What becomes of the matter collected by the blood in the course of its circulation?
We have already explained that carbon is thrown off from the lungs in the form of carbonic acid gas. But there are many other matters to be separated from the venous blood, and its purification is assisted by the action of the liver, which is supplied with a large vein, called the portal vein, which conveys into the substance of the liver, a large proportion of the venous blood, from which that organ draws off those matters which form the bile, and other matters which are transmitted with the bile to the bowels. The liver and the lungs, therefore, are the great purifiers of the venous blood. But there are also smaller organs that assist in the same work.
Fig. 53.—SHOWING THE DISTRIBUTION OF BLOOD THROUGH BRANCHES OF THE AORTA.
A. The aorta.
B. Branches given off for the aorta to supply one portion of the intestines.
C. Branches given off by the aorta to supply other portions of the intestines. A complete communication may be traced between these vessels from the origin of one to that of the other.
D. The pancreas, or sweetbread, a large gland that forms the pancreatic juice, which it pours in through the duct. (See [Fig. 50].)
E E E. The large intestines, forming the termination of the alimentary canal.
CHAPTER XLIV.
902. Why when we cut our flesh does it heal?
Because the blood coagulates over the cut, and throws out a kind of lymph, which forms an incipient flesh, and excludes the air while the blood-vessels are engaged in repairing the part.
"And God said, Let us make man in our own image, after our likeness; and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing."—Gen. i.
903. Why, since all the substance of the body undergoes change, do we preserve the same features throughout our lives?
Because our substance changes in the minutest atoms; and each separate atom has a life of itself, the maintenance of which preserves the unity and permanence of the whole.
904. Why do moles upon the skin continue permanent, while bruises and wounds disappear?
Because moles are themselves organised formations, and repair themselves just as any other part of the body does. But bruises and wounds are the result of accidental disturbances, which in course of time become removed.
905. Why do the marks of deep cuts sometimes remain?
If the cut is so deep and serious as to destroy the system of vessels which supply and repair the part, then it is evident that they cannot work so perfectly as when in their sound condition. Their functions are, therefore, interfered with, and instead of having flesh uniform with the other parts of the system; there results a scar, or a wound imperfectly repaired.
906. Why when we hold our hands against a candle-light do we perceive a beautiful crimson colour?
Because the fluids and vessels of the body are in some degree transparent, and the thin textures of the sides of the fingers allows the light to pass, and shows the beautiful crimson colour of the blood.
If the web of a frog's foot be brought in the field of a good microscope, and set against a strong light, the blood may be seen in circulation, with the most wonderful effect. Each vessel, and every globule of blood, can be seen most distinctly, and the junction of the arteries and veins can be clearly traced. The little boats of nutrition may be seen chasing each other in rapid succession, and when the animal exerts itself to escape, the flow of the blood increases; and not unfrequently, under these circumstances of agitation, have we seen two or three blood discs struggling together to enter a vessel that was too small for them. Again and again they have endeavoured to find a passage, until one of them happening to slip forward, got away, followed by the others!
"Know ye that the Lord he is God: it is he that hath made us, and not we ourselves: we are his people, and the sheep of his pasture."—Psalm c.
907. Why does the flesh underneath the nails look red?
Because the transparent texture of the nails enables us to see the colour of the vascular structure that lies underneath the skin.
Vascular.—Full of vessels. In this instance, full of capillary blood-vessels.
908. Why have we nails at our fingers' ends?
Because they give firmness to the touch, and enable us to apply the extremities of the fingers to many useful purposes for which they would otherwise be unfitted. They enable us to press the tips of the fingers, where the highest degree of sensitiveness prevails, so as to bring the largest amount of nervous perception into the sense of touch.
909. Why do white spots occur upon the nails?
Because the vascular surface underneath is attached to the horny texture of the nail; but by knocks and other causes, the nail sometimes separates in small patches from the membrane below, and becomes dry and opaque.
910. Why is there a circular line of whitish colour at the root of the nail?
Because there the nail is newly formed by the vascular substance out of which it grows, and has not yet assumed its proper horny and transparent nature.
911. Why is the eyeball white?
Because the blood-vessels that supply its surface are so very fine that they do not admit the red corpuscles of the blood.
912. Why does the eyeball sometimes become blood-shot?
Because, under exciting causes of inflammation, the blood-vessels become distended, and the red corpuscles enter, producing a net-work of red blood-vessels across the white surface of the eye.
Because the lips are formed of the mucous membrane that lines the body internally, and covers the surface of most of the internal parts. This membrane contains a great number of minute red vessels, which give softness and moisture to the surface. A very beautiful illustration of the softness, moisture, and delicate colour of the mucous membrane is afforded by turning up and examining the under surface of the upper eyelid.
"Hast thou not known, hast thou not heard, that the everlasting God, the Lord, the Creator of the ends of the earth, fainteth not, neither is weary? there is no searching of his understanding"—Isaiah xl.
914. Why do delicate persons look pale and languid?
Because, generally from the want of exercise and fresh air, their blood is deficient of the healthy proportion of red corpuscles.
915. Why does exercise and fresh air impart to healthy persons a red and fresh appearance?
Because the redness of the blood is due to the amount of oxygen which it contains, and air and exercise oxygenise the blood, and diffuse it throughout the system.
916. How is the blood propelled through the arteries?
By the very powerful contraction (and alternate dilation) of the thick muscles of the heart, assisted also by the muscular cords of the blood-vessels themselves, and in many instances by the compression of the muscles in which the arteries lie embedded.
917. Why are the capillary arteries capable of receiving the great quantity of blood sent out through the larger vessels?
Because the capillary vessels are so numerous, that though they are infinitely smaller, they are capable of receiving in their minute tubes the whole of the quantity of blood transmitted to them through the larger vessels.
918. Why, when we sit with our legs crossed, do we see the foot that is raised move at regular intervals?
Because the pressure upon the muscles of the leg retards the progress of the blood until it forces itself through the compressed vessels, and thereby imparts a pulsation which moves the leg and foot.
919. Why are capillary blood-vessels found in every part of the system?
Because it is through these small vessels alone that the substances of the body are renewed and changed. Even the larger blood-vessels do not sustain themselves upon the blood which they contain, but receive into their coats numerous capillary vessels by which they are nourished.
"All my bones shall say, Lord, who is like unto thee, which deliverest the poor from him that is too strong for him, yea, the poor and the needy from him that spoileth him?"—Psalm xxxv.
920. How much blood does the human body contain?
From twenty-five to thirty-five pounds. (See [623].)
921. How does the blood ascend in the veins, in opposition to gravitation?
In addition to the muscular coats of the veins, and the influence of muscular action upon them, there are in the veins numerous semi-circular valves, which are not found in the arteries. These valves extend from the sides of the veins in such a manner that they allow the free passage of the blood upwards, but a backward motion of the blood would expand the cup-like valves and stop the passage; so that the blood can only move in one direction, and that towards the heart.
922. How frequently does the total amount of blood circulate through the system?
The blood circulates once through the body in about two minutes. If, therefore, we estimate the amount of blood at twenty-four pounds, it follows that no less than twelve pounds of blood pass through the heart every minute; and it is estimated that if the blood moved with equal force in a straight line it would pass through one hundred and fifty feet in a minute.
CHAPTER XLV.
923. How many bones are there in the human body?
There are two hundred and forty-six, and they are apportioned to the various parts of the body in the following numbers:—
| Head | 8 |
| Ears | 6 |
| Face | 14 |
| Teeth | 32 |
| Back-bone and its base | 26 |
| Chest, &c. | 26 |
| Arms and Hands | 64 |
| Legs and Feet | 62 |
| Small moveable bones | 8 |
"Our bones are scattered at the grave's mouth, as when one cutteth and cleaveth wood upon the earth."—Psalm cxli.
924. Of what substances are the bones composed?
One hundred parts of bone consist of
| Cartilage | 32·17 | parts |
| Blood-vessels | 1·13 | " |
| Carbonate of lime | 11·30 | " |
| Phosphate of lime | 51·04 | " |
| Fluate of lime | 2·00 | " |
| Phosphate of Magnesia | 1·16 | " |
| Soda, chloride of sodium | 1·20 | " |
| ——— | ||
| 100·00 |
925. What are the uses of the bones?
They protect soft and delicate organs; they form a framework to which the organs are attached, and by which they are kept in their places; and they supply a mechanism, by which the motions of the body are produced, in combination with the muscles.
926. Why is the brain placed within the skull?
Because that delicate and vital organ, being the centre and the root of the nervous system, requires a position of the greatest safety.
927. Why are the bones that constitute the vertebræ (back-bone) hollowed out, so as to form a continuous groove?
Because through that groove the spinal cord passes out from the brain. Being in the centre of that column of bones, the spinal cord receives from them a similar protection to that which the brain obtains from the skull.
928. Why is the head set upon the neck?
Because in that position it obtains the freest motion, can turn in any direction, and is placed relatively to the other parts of the body, in that situation where it acquires the greatest possible advantage.
929. Why are the eyes placed in the sockets of the skull?
Because the bones of the skull afford protection to the delicate and complicated structure of the eyes, and supply points of attachment, and grooves, by which the muscles are enabled to turn the eyes freely, and thereby extend the field of vision.
"Thus saith the Lord God unto these bones, Behold I will cause breath to enter into you, and ye shall live:"
930. Why are the bones of the skull arched?
Because in that form they acquire greater strength, and hence the utmost degree of safety is combined with extreme lightness of material.
Fig. 54.—VIEW OF THE BONES OF THE THORAX, OR CHEST, SHOWING THE PROTECTION AFFORDED TO THE ORGANS OF CIRCULATION AND RESPIRATION.
A. The sternum, or breast-bone.
B B. The ribs, which rise a little from behind, and fall as they come forward, by which they acquire a greater flexibility.
C C. The cartilaginous points of the short ribs, by which their expansive and compressive powers are much increased.
D E. Part of the vertebral column, or back-bone.
931. Why are the bones of the skull divided by sutures (seams), with points which fit into each other like small teeth?
Because, by that arrangement, concussions of the skull, which might be fatal to the brain, are deadened, and injuries from accident greatly modified.
"And I will lay the sinews upon you, and will bring up flesh upon you, and cover you with skin, and put breath in you, and ye shall live; and ye shall know that I am the Lord."—Ezekiel xxxvii.
932. Why are the heart, lungs, &c., placed within the chest?
Because the functions of those organs require considerable space, while their importance in the system of life, renders it essential that they should be securely protected from the probabilities of accident.
933. Why are the heart and lungs enclosed for protection in a series of ribs, and not in a close case, like the brain?
Because, by the inflation and contraction of the lungs, their capacity is constantly changing. When man takes a moderate inspiration, he inhales about thirty cubic inches of air, and the lungs increase in size one-eighteenth of their whole capacity. Consequently, were they enclosed in a frame of fixed dimensions, it must needs be, to that extent at least, larger than is necessary, when the frame is made to dilate and contract with the capacity of the lungs.
So perfect is the Almighty contrivance, that not only are the ribs made to protect the lungs, but, by their elasticity, and the contractions and dilations of the muscles which lie between them, they assist the lungs in their labours, and work with them in perfect harmony.
Fig. 55.—SECTION OF THE KNEE JOINT, SHOWING THE CELLULAR STRUCTURE OF BONE, BY WHICH LIGHTNESS AND STRENGTH ARE OBTAINED.
934. Why are the bones of the arms, legs, &c., made hollow?
Because lightness is thereby combined with strength. There is a provision by which, in the extremities of bones, where an enlarged surface is required, lightness is still combined with the necessary degree of strength.
The bones are made up of a cellular formation; and this generally occurs in parts which are much called into action, in the various movements of the body.
A. Lower part of the bone of the thigh.
B. Head of the bone of the leg.
C. The knee cap, showing its relation to the other bones, and the manner in which it is enclosed by the tendons seen at [Fig. 58].
![[Fig. 58]](#i-232.jpg){kind=link}
D. A pad of fat, lessening the friction of the bones, and modifying the shocks produced by jumping, &c.
"Again he said unto me, Prophesy upon these bones, and say unto them, O ye dry bones, hear the word of the Lord."—Ezekiel xxxvii.
935. Why are the bones of the arms and legs formed in long shafts?
Because a considerable leverage is gained, by which the advantages of quickness of motion, and increase of mechanical power, are secured.
936. Why are the bones of the hands and feet numerous and small?
Because the motions of the hands and feet are very varied and complicated. There are no less than twenty-eight bones in one hand and wrist; and about as many in a foot and ankle. To these are fastened a great number of ligaments and muscles, by which their varied compound movements are controlled. But for the complexity of the mechanism of our hands and feet, our motions would be extremely awkward, and many of the valuable mechanical inventions which now benefit mankind, could never have been introduced. The bones of the hands and feet are in number equal to one-half of the whole of the bones of the body.
CHAPTER XLVI.
Ligaments consist of bands and cords of a tough, fibrous, and smooth substance, by which the bones are bound together and held in their places, allowing them freedom to move, and supplying smooth surfaces over which they glide.
938. Why are the joints bound with ligaments?
Because the bones would otherwise be constantly liable to slip from their places.
"That which is born of the flesh is flesh; and that which is born of the Spirit is spirit."—John iii.
Tendons are long cords, of a substance similar in its nature to cartilage, by which the muscles are attached to the bones.
Fig. 56.—SHOWING A BALL AND SOCKET JOINT, AND THE MANNER IN WHICH LIGAMENTS ARE EMPLOYED TO HOLD BONES IN THEIR POSITIONS.
A. The ball, or head of the thigh bone.
B. The socket, showing the ligament in the socket, which holds the head of the bone in its place, but allows it free motion.
C. Ligaments tied from bone to bone, giving firmness to the parts.
940. Why are tendons used to attach the muscles to the bones?
Because, by this arrangement, the large muscles by which the extremities are moved, may be placed at some distance from the bones upon which they act, and thus the extremities, instead of being large and clumsy, are small and neat.
941. How many muscles are there in the human body?
There are about four hundred and forty-six muscles that have been dissected and described, and the actions of which are perfectly understood. But there is probably a much larger number of muscles, and of compound actions of muscles, than the skill of man has been able to recognise.
"All flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds."—Corinthians xvi.
Fig. 57.—ILLUSTRATION OF THE RELATION OF MUSCLES, TENDONS, AND BONES.
942. What is the constitution of a muscle?
Every muscle is made up of a number of parallel fleshy fibres, or threads, which are bound together by a smooth and soft tissue, forming a sheath or case to the muscle, and enabling it to glide freely over the surfaces upon which it moves.
A. Lower extremity of the muscle which draws the fore-arm towards the upper-arm, bends the elbow, raises the hand to the head, and is powerfully exerted in pulling, lifting, &c.
C. A muscle which gives off four long tendons, which pass under the ligaments of the wrist, one to each finger, and by which the fingers are bent upon the palm of the hand, as in grasping, &c.
F. Tendon of a muscle which draws the little finger and the thumb towards each other.
The ligaments may be seen enfolding the finger-joints, and also crossing the wrist, underneath the tendons.
The muscles are compressed into tendinous cords at their ends, by which they are united to the bones.
They are arranged in pairs, having reciprocal actions—each muscle having a companion muscle by which the part which it moves is restored to its original position, when the influence of the first muscle is withdrawn, and the stimulus given to bring back the part.
943. Why can we raise our fingers?
Because muscles which lie on the fore-arm, and have their tendons fastened at the ends of the fingers, contract, and by becoming shorter, draw the fingers upward, and towards the arm.
"Thou hast clothed me with skin and flesh, and hast fenced me with bones and sinews."—Job xi.
944. Why can we throw back the fingers after they have been raised?
Because the muscles at the back of the arm, whose tendons are attached to the back of the fingers, contract and restore them to their former position.
945. What degree of strength do the muscles possess?
The degree of strength of a muscle depends upon the healthy condition of the muscle, the amount of stimulus which it receives at the time of exertion, and the manner in which its powers are applied.
The great muscle of the calf of the leg has been found, when removed from a dead body, to be capable of sustaining a weight equal to seven times the weight of the entire body.
But the contractile power of the living muscles is very great: the thigh bone has frequently been broken by muscular contractions in fits of epilepsy. And in cases where there has been a dislocation of the thigh, the head of the thigh-bone being thrown out of its socket, ([Fig. 56]) it has been found necessary to employ strong ropes, attached to a wheel turned by several hands, in order to overcome the contraction of the excited muscles, and to enable the operator to restore the bone to its place.
![[Fig. 56]](#i-229.jpg){kind=link}
946. What is the stimulus which sets the muscles in action?
The muscles are excited to action by the nerves, which they receive from the spinal cord.
947. Why does it require the influence of the will to set the arms in motion?
Because the muscles which form their mechanism are voluntary muscles—that is, they are subject to the will of man, and influenced by impulses directed to them through the nervous system by the mind, which is the governing power.
"And he took him by the right hand, and lifted him up; and immediately his feet and ankle bones received strength."—Acts iii.
948. Why does the heart beat without any effort of the will?
Because the muscles of the heart are involuntary muscles—that is, they are independent of the will, and receive a continuous nervous stimulus which is not under the controul of the mind.
Fig. 58.—MUSCLES AND VESSELS OF THE LEG AND FOOT.
A. A large ligament, which covers the knee pan, or moveable bone of the knee, by which the ends of the bones of the thigh and leg are kept from slipping over each other.
B. A muscle which passes underneath the cartilages of the ankle, and gives off four tendons, which are distributed to the toes, and by which they are extended in elongating the foot, walking, &c.
C. Part of the muscle which forms the fleshy bulb of the calf of the leg, and which terminates in the large tendon attached to the heel, called the tendon of Achilles.
D. One of the ligaments which bind the tendons and the bones of the ankle.
E. Arteries proceeding from the large vessel descending the leg, by which the toes are supplied.
949. Why are the muscles of the arms, &c., made subject to the controul of the will?
Because, as they supply the mechanism through which we adapt ourselves to our varying wants and circumstances, it was necessary that they should be placed under the controul of the mental power, and be moved only in accordance with man's necessities.
"If thou sayest, Behold, we knew it not; doth not he that pondereth the heart consider it? and he that keepeth thy soul, doth not he know it? and shall not he render to every man according to his works?"—Proverbs xxiv.
950. Why are the motions of the heart, &c., made independent of the will?
Because, as the necessity for the heart's motion is fixed and unalterable, the constant motion of the heart could be best secured by giving it a fixed nervous influence, by which it might be unfailingly prompted to fulfil its functions.
If the movements of man's heart were subject to his will, he would be constantly required to regard the operations of that organ; and so large an amount of mental care and physical exertion would have to be employed in that direction, that man's sole work would be to keep himself alive. Hence we see the goodness of the Creator in giving life to man, and in keeping the vital impulses under his divine care.
CHAPTER XLVII.
The nerves are branches of the brain and the spinal cord; they are distributed in great numbers to all the active and sensitive parts of the body.
The spinal cord is a long and large cord of nervous matter, which extends from the brain through a continuous tube formed by corresponding hollows in the bones of the back. It serves as a nervous trunk for the distribution of nerves, just as the aorta distributes branches of blood-vessels.
953. Why is the spinal cord placed in the grooves formed by the back-bone?
Being a very vital part of the system, and from the delicacy of its structure liable to injuries, it is set in the back-bone for protection; and so great is its security that it is only by force of an unusual kind that it can be injured.
"A sound heart is the life of the flesh: but envy is the rottenness of the bones."—Proverbs xiv.
954. How can branches proceed from it, if it is so securely encased in bone?
Because in the bones, on each side of the spinal cord, there are smaller grooves for the transmission of the nervous branches.
955. Of what does the nervous system consist?
Of the brain, the spinal cord, and the branches which are called nerves.
Fig. 59.—SHOWING THE DISTRIBUTION OF NERVES AND VEINS, AND ILLUSTRATING THE MANNER IN WHICH THEY PASS THROUGH THE FLESH TO REACH THE PARTS TO WHICH THEIR FUNCTIONS BELONG.
A. B. Veins of the fore-arm.
B. Canal formed in the muscle, through which a trunk-vein emerges.
C. Canal formed in the muscle, through which a large nerve emerges.
D. Canal through which a vein enters to communicate with the deep muscles of the arm.
956. What is the constitution of a nerve?
It consists of a thin membrane, or sheath, surrounding a greyish oily matter, which forms the nervous marrow. In the centre of this marrow is usually found a small fibre, which is supposed to be the essential part of the nerve; and most nerves consist of a number of these sheaths enclosing fibres running in parallel directions.
957. What is the nervous fluid?
The term nervous fluid is used to express our ideas of the mode by which the brain and spinal cord influence the remote parts: just as we say the electric fluid, without knowing that such a fluid exists. It is the most convenient form of expression.
958. How many classes of nerves are there?
There are:—
1. The nerves of motion.
2. The nerves of sensation.
3. The nerves of special sense.
4. The nerves of sympathy.
"Having many things to write unto you, I would not write with paper and ink; but I trust to come unto you, and speak face to face, that our joy may be full."—II John.
959. What are the nerves of motion?
The nerves of motion are those which, in obedience to the will, stimulate the muscles to act, and apportion the amount of stimulation they convey to the degree of exertion required.
Fig. 60.—MUSCLES OF THE HEAD AND FACE, WITH NERVES DISTRIBUTED THERETO.
A A A. The facial nerve emerging from underneath the ear, and distributing branches to the cheeks, temple, forehead, &c. This nerve excites the muscles of the face, and is chiefly instrumental in producing the expressions of the countenance under the changing emotions of the mind.
B B B. Muscles by which various motions are imparted to the head, face, mouth, &c., under the stimulus of the nerves.
960. What are the nerves of sensation?
The nerves of sensation are those which impart a consciousness to the brain that its commands to the nerves of motion have been obeyed, and how far they have been fulfilled.
"Oh that men would praise the Lord for his goodness, and for his wonderful works to the children of men."—Psalm cvii.
Let us perform a simple experiment, which will more clearly illustrate the phenomena of motion and of sensation, which we are now describing, than a great deal of writing upon the subject. You hold in your hand this book: close it, and set it upon the table; lay your hands passively upon your lap, and then will your hand, to take up the book, which is the same as to say, command your hand to take up the book. What occurs? The hand, immediately obeying your desire, stretches forward to the book, and takes hold of it. How do you know that you have hold of it? You see that you have: but were your eyes closed, you would be equally aware that the hand had reached the book, and fulfilled your wishes. It is by the nerves of sensation that you are made aware that the hand has fulfilled your instructions.
Consider what took place in the simple action. In the first instance, a desire arose in your mind to take up the book. The brain is the organ of the mind; and having branches either proceeding from itself, or from the spinal cord, to every part of the body—branches that traverse like telegraphic wires throughout every part of the system,—it transmitted instructions along the nerves that proceed to the muscles of the arm and hand, directing them to take up the book. This was done instantly; and as soon as it was done you became conscious that your will had been obeyed—because the nerves sent back a sensation to the brain acquainting it that the book had been taken up, and that at the moment of the dispatch it was in the firm hold of the hand.
In all the varied motions of the body this double action of the nerves takes place. It is obvious that without an outward impulse from the brain, upon which the desire of the mind first made an impression, no motion of the muscles of the arm and the hand could have taken place; and it is also obvious that without an inward impulse from the nerves to the brain you would not have known that the muscles had fulfilled your instructions. The hand might have dropped by the side of the book, or have gone too far, or not far enough, and you would not have been aware of the result, but for an inward communication through the nerves.
We are not now speaking of the nerves which endow us with the sense of feeling, because they are regarded as separate and distinct from those nerves that produce in us consciousness of muscular response. When we walk, rise, or sit, we are made conscious, without any special feeling being exerted, that the muscles have placed the limb, or the body, in the desired position, that it is set down safely and firmly, and that we may repose upon it securely without further attention. We refer the impressions made by the book upon the nerves of the hand, and which enable us to tell whether it feels hot or cold, whether its surface is rough or smooth, and so on, to the special sense of feeling. The consciousness of muscular action is a separate and distinct function; and it is generally believed that the same nerves that convey the command of the will outward, bringing back the intimation that the will has been obeyed, but that different fibres of the nerves convey the outward and the inward impulses. A single nerve may therefore be likened to a double wire connected with the electric telegraph: one transmitting despatches in one direction, and the other in the opposite direction.
961. What are the nerves of special sense?
The nerves of special sense are those through which we hear, see, feel, smell, and taste.
"For the Lord seeth not as man seeth; for man looketh on the outward appearance, but the Lord looketh on the heart."—Samuel xvi.
962. What are the nerves of sympathy?
The nerves of sympathy, or the system of sympathetic nerves, are those which are distributed to the internal organs, and which are independent of the will. They regulate the motions of the heart, the lungs, the stomach, &c., and stimulate the organs of secretion, so that those organs work in harmony with each other.
As the internal organs are all more or less dependent upon each other, and unite their functions for similar ends, it is obvious that there should prevail among them a mutual consciousness of their state. Otherwise, when the stomach had formed chyme, the liver might have no bile ready to fulfil its office; the absorbents might be in a state of rest at the moment when nutrition was set before them; and the heart might beat slowly, while the lungs were in active exertion to obtain additional blood to support an active exercise. The sympathetic system of nerves therefore regulates and harmonises these internal functions.
CHAPTER XLVIII.
Because the light which is reflected from them enters our eyes and produces images of their forms upon a membrane of nerves called the retina, just as images are produced upon a mirror.
964. Why does this enable us to see?
Because the membrane which receives the images of objects is connected with the optic nerve which transmits to the brain impressions made by the reflections of light, just as other nerves convey the effects of feeling, hearing, tasting, &c.
965. Why are we enabled to move our eyes?
Because various muscles are so placed in relation to the eyeball, that their contraction draws the eye in the direction required. We are thus enabled to adjust the direction of the eye to the position of the objects we desire to see, in other words to set the mirror in such a position that it will receive the reflection. (See [517].)
"Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun."—Ecclesiastes xi.
966. Why are we enabled to see large objects upon so small a surface?
Because the lenses and humours of the eye collect the rays of light coming from every direction, and, bringing them into a focus, transmit them to the retina, where each ray impresses upon the nervous surface the qualities it received from the object which reflected it.
Fig. 61.—THE EYEBALL AND ITS MUSCLES.
A. Portion of bone through which the optic nerve passes in its communication between the brain and the eye.
B. The optic nerve, from before which an external muscle has been cut away, leaving its two attachments.
C. The globe of the eye.
D. The muscle which turns the eye outward, and which is counteracted by a muscle on the other side.
E. The muscle which passes through a loop, or staple of cartilage I, and turns the eye obliquely. It is counteracted by a muscle situated underneath.
F. The muscle situated underneath, which turns the eyeball upwards, and is counteracted by
G. The muscle which turns the eyeball downwards.
H. The muscle attached to a bone which turns the eyeball upwards.
I. The cartilaginous loop through which a muscle passes.
J. The front chamber of the eye filled with a clear fluid.
K. Fragment of the bone by which one of the muscles is fastened.
967. Why do some persons squint?
Because it sometimes happens that a muscle of the eye acts too powerfully for its companion muscle, and draws the eye too much on one side.
968. Why does the pupil of the eye look black?
Because the pupil is an opening through which the rays of light pass into the chamber of the eye. There is, therefore, nothing in the pupil, of the eye to reflect light.
"Keep me as the apple of thine eye; hide me under the shadow of thy wings."—Psalm xvii.
969. Why is the pupil of the eye larger sometimes than at others?
Because the iris, a ring of extremely fine muscles which surround the pupil, contracts when too much light falls upon the retina, and dilates when the light is feeble. It therefore enlarges or diminishes the size of the pupil to regulate the admission of light.
Fig. 62.—SECTION OF THE EYE SEEN FROM BEHIND.
A. The pupil of the eye through which the light enters.
B. The iris, which dilates or contracts, and thereby increases or lessens the size of the pupil.
C. The three coats of the eye, called the sclerotic, choroid, and retina.
D. The ciliary processes, or hair-like muscles, which have a slight vibratory motion which they impart to the fluids of the eye.
E. The dark coat of the choroid, the coat forming the retina removed.
Because the field of vision is thereby much extended; the intensity of sight is also increased, the impressions upon the brain being clearer and better defined, just as in a stereoscope the effect of vision is heightened by a double picture; the sense of sight being more constantly exercised than any other sense during our waking moments, one eye is frequently called upon to give rest to the other; and the important faculty of vision, being endangered by the necessary exposure of some parts of the eye, and the equally necessary delicacy of an organ formed to receive impressions from so ethereal an element as light, is rendered the more secure to us, since though one eye may become enfeebled, diseased, or wholly lost, the other eye will retain the blessing of sight.
"The eyes of the Lord are upon the righteous, and his ears are open unto their cry."—Psalm xxxiv.
971. Why, having two eyes, and each eye receiving a reflection upon its retina, does the brain experience only one impression of an object?
Because, besides those optical laws which bring upon the two retinas the exactly corresponding images of the same objects, the optic nerves meet before they reach the brain, and blend the impulses which they convey.
972. Why are the eyes provided with eyelids?
Because the eyes require to be defended from floating particles in the air, and to be kept moist and clean. The eyelids form the shutters of the eye, defending it when waking, by closing upon its surface whenever danger is apprehended, moistening its surface when it becomes dry, and covering it securely during the hours of sleep.
973. Why are the eyelids fringed with eyelashes?
Because the eyelashes assist to modify the light, and to protect the eye, without actually closing the eye-ids. When the eyelids are partially closed, as in very sunny or dusty weather, the eyelashes cross each other, forming a kind of shady lattice-work, from the interspaces of which the eye looks out with advantage, and sees sufficiently for the guidance of the body.
974. Why are we able to see at long or short distances?
Because the crystalline lens of the eye is a moveable body, and is pushed forward, or drawn back by fine muscular fibres, according to the distances of the objects upon which we look. By these means its focus becomes adjusted.
Because, by the repeated action of winking, the eye is kept moist and clean, and the watery fluid secreted by little glands in the eyelids, and at the sides of the eye, is spread equally over the surface, instead of being allowed to accumulate. But the action of winking, or brightening the eye, is so instantaneous that it does not impede the sight.
"And the eye cannot say unto the hand, I have no need of thee; nor again the head to the feet, I have no need of you."—Corinth. xii.
976. Whence are the humours and secretions of the eye derived?
From the blood, which flows abundantly to the eyes, and is circulated in capillary vessels that are spread out upon the membranous coats of the eye-balls.
Fig. 63.—SECTION OF THE EYE.
A and B. The sclerotic, choroid, and retina, the three layers or coats which form the walls of the globe of the eye, and enclose its humours.
C C. The iris.
D. The front chamber of the eye, filled with watery humour.
E. The pupil, through which the rays of light pass to
F. The crystalline lens.
G G. The vitreous humour enclosed in cells formed by the hyaloid membrane.
H. An artery which supplies blood to the crystalline lens, and which passes through the centre of the optic nerve.
G. The optic nerve, showing the sheath in which the nerve is enclosed.
977. Why do tears form in the eyes?
Because, under the emotions of the mind, the circulation of blood in the brain, and in its nearest branches, becomes considerably quickened. The eyes receive a larger amount of blood, and the secretion of the lachrymal glands being increased, the fluid overflows, and tears are formed. The use of tears is probably to keep the eyes cool during the excitement of the brain. They are formed also during laughing, but less frequently.
"If the whole body were an eye, where were hearing? if the whole were hearing, where were smelling?"—Corinthians xii.
978. Why do we feel inconvenienced by sudden light?
Because an excess of light enters the eye before the iris has had time to adjust the pupil to the amount of light to be received.
979. Why if we look upon a very bright light, and then turn away, are we unable to see?
Because the iris has so reduced the pupil while we were looking at the bright light, that immediately upon turning to a darker object, the pupil is too small to admit sufficient rays to enable us to see.
Fig. 64.—CAPILLARY BLOOD-VESSELS OF THE EYE.
A A. Capillary veins distributed over the sclerotic coat.
B. One of the trunks of the optic nerve.
C. A nerve communicating with the ciliary processes.
D. A vein running parallel with the nerve to the ciliary processes.
E. Side view of the iris.
980. Why do we see better after a short time?
Because the iris has relaxed and enlarged the pupil, therefore we receive more rays of light from the comparatively dark object, and are enabled to see it more clearly.
981. Why do cats, bats, owls, &c., see in the dark?
Because their eyes are made highly sensitive to small quantities of light. It is also believed that there are certain properties of light which affect their eyes, but do not affect ours. In other words, that there are some rays which are luminous to them which are not luminous to us. Hence they find light in what we call darkness.
"He that hath ears to hear, let him hear."—Matthew xi.
982. Why does the pupil of a cat's eye appear nearly closed by day?
Because the cat's eye is so sensitive to light that the iris closes the pupil almost entirely to shut out the too powerful light.
CHAPTER XLIX.
Because the tympanum of the ear receives impressions from sounds, and transmits those impressions to the brain in a similar manner to that in which the retina of the eye transmits the impressions made upon it by light.
984. Why is one part of the ear spread out externally?
The external ear is a natural ear-trumpet, and serves to collect the vibrations of sound, and to conduct them towards the internal ear.
985. Why is the ear allowed to project, whilst the eye is carefully enclosed?
Because the external ear, being formed of tough cartilaginous substance, and being very simple in its organisation, is but little liable to injury.
986. Why do hairs grow across the entrance of the ears?
Because they prevent the intrusion of insects, and of particles of dust, by which otherwise the faculty of hearing would be impaired.
The insect called the earwig is popularly supposed to be so named from its tendency to get into the human ear, and cause pain and madness by penetrating to the brain. An earwig, however, is no more likely to get into the ear than any other insect whose habit it is to penetrate the corollas of flowers; and should an insect enter the ear, it could get no further than the membrane of the tympanum, which spreads all over the auditory passage, just as the parchment of a drum spreads over the entire circumference of that instrument. The fact is, that the wing of the insect, when spread, resembles the external ear in shape. It is similar to the wing of the stag beetle (see illustration), and this fancied resemblance of the wing of the insect to the ear of man may have given rise to the name of ear-wing, which became corrupted to earwig.
"Doth not the ear try words? and the mouth taste his meat."—Job xii.
987. Why is wax secreted at the entrance of the ear?
Because, by the peculiar resinous property which it possesses, it improves the sound-conducting power of the auditory canal through which it prevails.
Fig. 65.—THE STRUCTURE OF THE EAR.
A A. Glands which secrete wax in the walls of the tube of the ear.
B. The membrane of the tympanum, or drum of the ear, formed in the shape of a funnel.
C C. Bones which act as a sort of sounding-board to the ear, giving strength to the vibrations.
D. The Eustachian tube, which opens into the root of the mouth, and which serves to preserve an equilibrium in the density of the air occupying the tubes of the ear.
E and F. The labrynth of the ear, consisting of folds of membraneous tubes, filled with fluid, which serves to undulate with the vibrations of the tympanum, and thus gives clearness and precision to the sounds.
The auditory nerves are distributed in the tubes above described (the vestibule and the cochlea E F), and the nerves receive their impressions from the undulations of the fluid.
988. Why do we sometimes hear singing noises in the ear?
Because the ear is liable to inflammation from various causes, and when the blood flows unduly through the vessels of the ear it produces a slight sound.
"Apply thine heart unto instruction, and thine ears to the words of knowledge."—Proverbs xxiii.
989. Why do people become deaf?
Because the ear may be injured in various ways: the tympanum may be impaired, the fluid of the ear dried up, or the nerves be pressed upon by swellings in the surrounding parts. When, therefore, the mechanism of hearing is impaired, the sense of hearing becomes weakened, or altogether lost.
990. Why do persons accustomed to loud noises feel no inconvenience from them?
Because the sensitiveness of the nerves of the ear becomes deadened. They do not convey to the brain such intense impulses when they are frequently acted upon by loud sounds.
991. Why do persons engaged in battle often lose their hearing?
Because the vibrations caused by the sounds of artillery are so violent that they overpower the mechanism of the ear, and frequently rupture the connection of the fine nervous filaments with the textures through which they spread.
The violent concussions of the air produced by volleys of cannon, or by loud peals of thunder, have an overpowering effect upon persons nervously constituted, and upon the organ of hearing, which is more especially affected. As persons have been struck blind by intense light, so others have been deafened by intense sounds. In 1697 a butcher's dog was killed by the noise of the firing to celebrate the proclamation of peace. Two troops of horse were dismounted, and drawn up in a line to fire volleys. At the moment of the first volley a large and courageous mastiff, belonging to a butcher, was lying asleep before the fire. At the noise of the first volley the dog started up, and ran into another room, where it hid itself behind a bed; on the firing of the second volley, it ran several times bout the room, trembling violently; and when the third volley was fired it ran around once or twice with great violence, and then dropped down dead, with blood flowing from its mouth and nose. Persons who are painfully affected by loud noises should put a little wool in their ears when such noises are occurring; they will thereby save themselves from temporary inconvenience, and probably preserve the sense of hearing from permanent injury.
Because minute particles of matter, diffused in the air, come in contact with the filaments of the olfactory nerve, which are spread out upon the walls of the nostrils, and those nerves transmit impressions to the brain, constituting what we call the odour of substances.
"And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul."—Genesis ii.
Fig. 66.—SHOWING THE DISTRIBUTION OF THE NERVOUS FILAMENTS UPON SENSITIVE MEMBRANES.
A. The olfactory nerve, distributed in minute branches upon the membrane of the nostril.
B. The bulb of the olfactory nerve.
C. The roots from which the olfactory nerve originates.
D E. Nerves of the palate, showing the manner in which they are passed through the bones of the roof of the mouth.
993. Why do hairs grow across the passages of the nostrils?
Because they form a defence against the admission of dust and insects, which would otherwise frequently irritate the nervous structure of the nose.
994. Why are the nostrils directed downwards?
Because, as odours and effluvia ascend, the nose is directed towards them, and thereby receives the readiest intimation of those bodies floating in the air which may be pleasurable to the sense, or offensive to the smell, and injurious to life.
"Can that which is unsavoury be eaten without salt? or is there any taste in the white of an egg?"—Job vi.
995. Why is the nose placed over and near the mouth?
Because, as one of the chief duties of that organ is to exercise a watchfulness over the purity of the substances we eat and drink, it is placed in that position which enables it to discharge that duty with the greatest readiness.
CHAPTER L.
Because the tongue is endowed with gustatory nerves, having the function of taste as their special sense, just as the optic, the auditory, and the olfactory nerves, have their special duties in the eyes, ears, and nose.
997. Why do some substances taste sweet, others sour, others salt, &c.?
It is believed that the impressions of taste arise from the various forms of the atoms of matter presented to the nerves of the tongue.
998. Why do we taste substances most satisfactorily after they have remained a little while in the mouth?
Because the nerves of taste are most abundantly distributed to the under surface of the tongue; and when solid substances have been in the mouth a little while, they impregnate the saliva of the mouth with their particles and come in contact in a fluid solution with the gustatory nerves.
999. Why if we put a nub of sugar to the tip of the tongue has it no taste?
Because the gustatory nerves are not distributed to that part of the tongue.
"Wine is a mocker, strong drink is raging; and whosoever is deceived thereby is not wise."—Proverbs xx.
1000. Why, when we draw the tongue in, do we recognise the sweetness of the sugar?
Because the dissolved particles of sugar are brought in contact with the nerves of taste.
1001. Through what nerves are we made sensible of the contact of sugar with the tip of the tongue?
Through the nerves of feeling, which are abundantly distributed to the tongue to guide it in its controul over the mastication of food.
1002. Why do connoisseurs of wines close their mouths and distend their chins for a few seconds, when tasting wines?
Because they thereby bring the wine in contact with the under surface of the tongue, in which the gustatory nerves chiefly reside.
1003. Why do they also pass the fumes of the wines through their nostrils?
Because flavour, in its fullest sense, comprehends not only the taste, but the odour of a substance; and, therefore, persons of experience attend to both requisites.
The various conditions of taste are defined to be:—
1. Where sensations of touch are alone produced, as by glass, ice, pebbles, &c.
2. Where, in addition to being felt upon the tongue, the substance excites sensation in the olfactory nerves, as by lead, tin, copper, &c.
3. Where, besides being felt, there are peculiar sensations of taste, expressive of the properties of bodies, as salt, sugar, tartaric acid, &c.
4. Where, besides being felt and tasted, there is an odour characteristic of the substance, and essential to the full development of its flavours, as in cloves, lemon-peel, caraway-seed, and aromatic substances generally.
Because there are distributed to various parts of the body fine nervous filaments, which have for their special duty the transmission to the brain of impressions made upon them by contact with substances.
"The works of the Lord are great, sought out of all them that have pleasure therein."—Psalm cxi.
1005. In what parts of the body does the sense of touch more especially reside?
In the points of the fingers and in the tongue. By laying a piece of paper upon a table, and upon the paper a piece of cloth, on the piece of cloth a bit of silk, and on the bit of silk a piece of leather, so that the edge of each would be exposed to the extent of half-an-inch, it would be possible by the touch to tell when the finger passed successively over the leather, silk, cloth, or paper, and arrived on the table.
Those impressions of touch must have been communicated, with their extremely nice distinctions, to the sensitive nerves that lie underneath the skin, and must have been transmitted all the way through the arm to the brain, although the touch itself was so light as scarcely to be appreciable with regard to the force applied.
A hair lying on the tongue will be plainly perceptible to the touch of the tongue; and the surface of a broken tooth will often cause the tongue great annoyance, by the acute perception it imparts of the roughness of its surface.
The toes are also highly sensitive, though their powers of touch are seldom fully developed. Persons who have lost their arms, however, have brought their feet to be almost as sensitive as fingers. Blind persons increase, by constant exercise, their powers of touch to such a degree that they are able to read freely by passing their fingers over embossed printing; and they have been known to distinguish colours by differences in their grain, quite unappreciable by other persons.
1006. Why is feeling impaired when the hands are cold?
Because, as the blood flows slowly to the nerves, they are less capable of that perception of touch which is their special sense. The skin contracts upon the nervous filaments, and impairs the contact between them and the bodies which they touch.
1007. Why do the fingers prick and sting when they again become warm?
Because, as the warmth expands the cuticle, and the blood begins to flow more freely through the vessels, the nerves are made conscious of the movements of the blood, and continue to be so until the circulation is equally restored to all the parts.
"In the sweat of thy face shalt thou eat bread, till thou return to the ground; for out of it thou wast taken: for dust thou art, and unto dust shalt thou return."—Genesis iii.
1008. Why do persons whose legs and arms have been amputated fancy they feel the toes or fingers of the amputated limb?
Because the nervous trunk which formerly conveyed impressions from those extremities remains in the part of the limb attached to the body. The mind has been accustomed to refer the impulses received through that nervous trunk to the extremity where the sensations arose. And now that the nerve has been cut, the painful sensation caused thereby is referred to the extremity which the nerve supplied, and the sufferers for a time appear to continue to feel the part which they have lost.
CHAPTER LI.
Because the skin is filled with very minute pores, which act as outlets for a portion of the water of the blood, that serves to moisten and cool the surface of the body, and to carry away some of the matter no longer needed in the system.
1010. How is the perspiration formed?
By very small glands, which lie embedded in the skin. It is estimated that there are about 2,700,000 perspiratory glands distributed over the surface of the body, and that these glands find outlets for their secretion through no less than seven millions of pores.
1011. What is insensible perspiration?
Insensible perspiration is that transmission of watery particles through the skin which is constantly going on, but which takes place so gently that it cannot be perceived. It is, however, very important in its results, as no less than from twenty to thirty-three ounces of water may pass imperceptibly through the skin in twenty-four hours.
1012. What is sensible perspiration?
Sensible perspiration is that moisture which exudes upon the skin in drops large enough to be perceptible, when the body is heated by exercise or other means.
"And Elisha sent a message unto him, saying, Go and wash in Jordan seven times, and thy flesh shall come again to thee, and thou shalt be clean."—II kings v.
1013. Why does a sudden change from heat to cold bring on illness?
Because the effect of cold arrests the action of the vessels of the skin, and suddenly throws upon the internal organs the excretory labour which the skin should have sustained.
1014. Why does a chill upon the skin frequently produce inflammation of the lungs?
Because the lungs and the skin together discharge the chief proportion of the watery fluid of the body. When the skin's action is checked, the lungs have to throw off a much greater amount of fluid. The lungs, therefore, become over worked, and inflammatory action sets in.
1015. Why does cleanliness promote health?
Because every atom of dirt which lodges upon the surface of the body serves to clog and check the working of those minute pores, by which much of the fluid of the body is changed and purified.
In the internal parts of the system, the Creator has made ample provision for cleanliness. Every organ is so constituted that it cleanses and lubricates itself. Every surface of the inner body is perfectly clean, and as soft as silk.
Nature leaves to man the care of those surfaces which are under his immediate observation and controul; and he who, from idleness, or indifference to nature's laws, is guilty of personal neglect, opposes the evident intentions of the Creator, and must sooner or later pay the penalty of disobedience.
1016. Why does exercise promote health?
Because it assists all the functions upon which life depend. It quickens the circulation, and thereby nourishes every part of the body, causing the bones to become firm, and the muscles to become full and healthy. It promotes breathing, by which oxygen is taken into the system, and carbon thrown off, and thereby it produces a higher degree of organic life and strength than would otherwise exist. It promotes perspiration, by which, through the millions of pores of the skin, much of the fluid of the body is changed and purified. And it induces that genial and diffused warmth, which is one of the chief conditions of a high degree of vitality.
"Love not sleep lest thou come to poverty: open thine eyes, and thou shalt be satisfied with bread."—Prov. xx.
Because those organs which stimulate the mechanism of the body to act, themselves require rest and repair. When the brain and nerves arrive at that state, they make their condition known to the system generally, by indications which we denominate fatigue.
1018. Why, after rest, do we return invigorated to our labours?
Because the nervous system has accumulated, during the hours of rest, a fresh amount of that vital force which we call the nervous fluid, and by which the various organs of the body are excited to perform the duties assigned to them.
Sleep is understood to be that state of the body in which the relation of the brain to some parts of the body is temporarily suspended.
There are some parts of the body that never sleep: such are the heart, the lungs, the organs of circulation, and those parts of the nervous system that direct their operations.
But when sleep overtakes the system, it seems as if the relations of those parts under the controul of the will were temporarily suspended; as if, for instance, those nerves which move the arms, the legs, the eyes, the tongue, &c., were all at once unfastened, just as the strings of an instrument are relaxed by the turning of a key, or the throwing down of a bridge over which they were stretched.
What is meant by the temporary suspension of the relation of the brain to some parts of the body, may be thus explained. Notice a man when he sits dosing in a chair: at first his head is held up, the brain controlling the muscles of the neck, and keeping the head erect. But drowsiness comes on, the brain begins to withdraw its influence, and the muscles of the neck becoming as it were "unstrung," the head drops down upon the breast. But the sleep is unsound, and disturbed by surrounding noises. The brain is therefore frequently excited to return its influence to the muscles, and draw up the head of the sleeper. He gives a sudden start, every muscle is tightened in an instant, up goes the head, the eyes open, the ears listen, until a feeling of security and composure returns; the sleep again deepens, the nervous connection is again withdrawn, and then down drops the head as before.
"Yet a little sleep, a little slumber, a little folding of the hands to sleep: So shall thy poverty come as one that travelleth; and thy want as an armed man."—Proverbs xxv.
Dreams appear to arise from the excitement of the brain during those hours when its connection with the other parts of the living organism is suspended. For instance: a man dreams that he is pursued by a furious animal, and the mind passes through all the excitement of flying from danger; but the connection between the moving power, and the machinery of motion being suspended, no motion takes place. The same impressions upon the brain, when the nerves were "strung" to the muscles, would have caused a rapid flight, and a vigorous effort to escape from the apprehended danger.
1021. Why do suppers, when indigestible substances are eaten, produce dreaming?
Probably because, as the digestive organs are oppressed, and those parts of the nervous system which stimulate the organs of digestion are excited by excessive action, those portions of the brain which are not immediately employed by the digestive process are disturbed by that sympathy which is observed to prevail between the relative parts and functions of the body.
Because, as we become weary, the nervous impulses which direct the respiratory movements are enfeebled. It has been said that those movements are involuntary, and that the parts engaged in producing them are not subject to fatigue. But the operation of breathing is, to some extent, voluntary, though when we cease to direct it voluntarily, it is involuntarily continued by organs which know no fatigue.
When, therefore, we feel weary—still controuling our breathing in our efforts to move or to speak—there frequently arrives a period when, for a few seconds, the respiratory process is suspended. It seems to be the point at which the voluntary nerves of respiration are about to deliver their office over to the involuntary nerves; but the pause in the respiration has caused a momentary deficiency of breath, and the involuntary nerves of respiration, coming suddenly to the aid of the lungs, cause a spasmodic action of the parts involved, and a yawn, attended by a deep inspiration to compensate for the cessation of breathing, are the result.
"And it shall be, when they say unto thee, Wherefore sighed thou that thou shalt answer, For the tidings, because it cometh; and every heart shall melt, and all hands shall be feeble."—Ezekiel xxi.
Because the respiratory organs are excited by the presence of some body foreign or unnatural to them. A cough is an effort on the part of the air tubes to free themselves from some source of irritation. And so important are the organs of breathing to the welfare of the body, that the muscles of the chest, back, and abdomen, unite in the endeavour to get rid of the exciting substance.
Because particles of matter enter the nostrils and excite the nerves of feeling and of smell. In sneezing, as in coughing, the effort is to free the parts affected from the intrusion of some matters of an objectionable nature. And in this case, as in the former one, there is a very general sympathy of other organs with the part affected, and an energetic effort to get rid of the evil.
The action of sighing arises from very similar causes to those of yawning. But in sighing, the nervous depression is caused by grief; while in yawning, it is the result of fatigue. In sighing, the effect is generally erased by an expiration—in yawning by an inspiration. The mind, wearied and weakened by sorrow, omits for a few seconds to continue the respiratory process; and then suddenly there comes an involuntary expiration of the breath, causing a faint sound as it passes the organs of the voice.
Laughing is caused by the very opposite influences that produce sighing. The nervous system is highly excited by some external cause. The impression is so intense, and the mind so fixed upon it, that the respiratory process is irregular, and uncontrolled. Persons excited to a fit of laughter generally hold their breath until they can hold it no longer, and then suddenly there is a quick expiration causing eccentric sounds, the mind being too intently fixed upon the cause of excitement, either to moderate the sounds, or to controul the breathing.
"Except ye utter by the tongue words easy to be understood, how shall it be known what is spoken? for ye shall speak into the air."—Corinth. xiv.
Hiccough is caused by a spasmodic twitching of the diaphragm, a thin muscular membrane which divides the chest from the abdomen. It generally arises from sympathy with the stomach; and it is highly probable that the muscular twitches and jerks are so many efforts on the part of the diaphragm to assist the stomach to get rid of some undigested matter.
Snoring is caused by air sweeping through the passages that lead from the mouth through the nostrils, and which, in our waking moments, are capable of certain muscular modifications to adapt them to our breathing. But as in sleeping the nervous controul over them is withdrawn, they are left to the action of the air which, in sweeping by them, sets them in vibration.
We have endeavoured, by the employment of the simplest language, and by reference to some of the most familiar phenomena of nature, to impart to the reader a clear conception of those sublime laws which control our being, and afford evidence of the goodness and power of that Almighty God to whom we are indebted for the life that we enjoy, and the varied and beautiful existences which, to the rightly constituted mind, make the earth a vast aggregation of interesting objects. We will now, before we pass on to the final section of our work, review some of the more important facts that have been communicated, and devote a few pages to meditations upon the formation of the human body—that wonderful temple of which each of us is a tenant.
We have described man's organisation. What is that organisation for? It is to make use of the elements upon which man exists. The lungs make use of the air; the eye makes use of the light; the stomach, and the system generally, make use of water; every part of the body uses heat; and all parts of the system demand food. The hand feeds as constantly as the mouth. The mouth is the receptacle of food, by which the body is to be fed; the stomach is the kitchen in which food is prepared for the use of the body; and the blood-vessels are the canals through which the food is sent to those members of the body that are in need of it. When we speak of man's "organs" or "members," we speak of those parts of the living machinery by which the elements are used up, or employed, for man's benefit. And this view of the subject, bearing in mind that the body is held together as the temple of a living Spirit, superior to mere flesh and blood, gives us a higher and clearer perception of the distinction between the body and the soul than that which we might otherwise entertain. The body is a machine, working for the spirit, which is its owner. While the machine works, the spirit directs and influences its actions. But when the machine stops, the spirit resigns its power over a ruined temple, quits it, and flies to a region where, as a spirit, it becomes subject to a new order of existence consistent with its severance from earthly things and laws, and there it enters upon its eternal destiny, according to the judgments and appointments of God. It is no longer dependent upon a relation between spiritual and material laws.
"Not unto us, O Lord, not unto us, but unto thy name give glory, for thy mercy, and for thy truth's sake."—Psalm cxv.
Suppose that the air which man breathes, instead of returning from his lungs clear and imperceptible to sight, were tinged with colour; we should see, that every time a man breathed, the air would rush in a stream into his mouth, and then return again; and the air which returned would, being warm, be lighter than the outer air, and would rise upward over the man's head, where, cooling and mingling with the outer air, it would descend again. We do, in fact, see this action evidenced; when in winter time the cold condenses the vapour of the breath, we see the little cloud constantly rising before the breather's face, and dispersing in the surrounding air.
Is it not a wonderful thing that that clear and elastic substance, which you cannot feel, though it touches every part of your body, and which you cannot see, is composed of two distinct bodies, having very different properties; and that the two bodies can easily be separated from each other?
Air is of the first importance to life. Hence it is provided for us everywhere. We require air every second, water every few hours, and food at intervals considerably apart. Air is therefore provided for us everywhere. Whether we stand or sit; whether we dwell in a valley or upon a mountain; whether we go into the cellar under our house, or into the garret at the top of it, air is there provided for us. God, who made it a law that man should breathe to live, also sent him air abundantly, that he might comply with that law. And all that is required from man in this respect is, that he will not shut out God's bounty, but receive it freely.
As we have employed the idea that if the air were coloured we should have the opportunity of marking the process of breathing, let us enlarge upon this, and suppose that every time the air were returned from the lungs it became of a darker colour, the darkness denoting increasing impurity. If we placed a man in a room full of pure air, we should see the air enter his lungs, and sent back slightly tinged; but this would disperse itself with the other air of the room and scarcely be perceptible. As the man continued to breathe, however, each measure of air returning from the lungs would serve to pollute that abiding in the room, until at last the whole mass would become cloudy and discoloured, and we should see such a change as occurs when water is turned from a pure and clear state into a muddy condition. The air does become polluted with each respiration, and although it is colourless, it is as impure as if with every breath given off from the lungs it became of a dark colour in proportion to its impurity.
Thus we see how important it is that we should provide ourselves with pure air; and that, in seeking warmth and comfort in our houses, we should provide an adequate supply of fresh atmosphere—because it is more vital to life than either water or food.
Indeed, so constant is our requirement of air, that if we had to fetch it, for purposes of breathing, or simply to raise it to our mouths, as we do water when we drink, it would be the sole occupation of our lives—we could do nothing else. For this reason, God has sent the air to us, and not required us to go to the air. And the great error of man is, that in too many instances, he shuts off the supply from himself, and brings on disease and pain by inhaling a poisonous compound, instead of air of a healthful kind, which bears an adaptation to the wants of life.
"There is a natural body, and there is a spiritual body."—I Corinthians xv.
Whilst the rooms of our house are filled with air, it is otherwise with water, which we require in less degree than air. If we have not the artificial means by which water is brought to our houses, through the pipes of a water company, there is a spring or a pump in the garden; or in the absence of these, a good sound cask, standing at the end of our house, forming a receptacle to the water-pipes that surround it, provides us with a supply of water distilled from the clouds. If we were to drink a good draught of water once a day, that would be sufficient for all the purposes of life, as far as regards the alimentary uses of water. Man is, therefore, allowed to go to the stream for his drink, and is required to raise it to his lips at those moments when he uses it.
Although, in breathing, man separates the oxygen of the air from the nitrogen thereof, he does not separate the oxygen of the water from the hydrogen. Water, in fact, undergoes no change in the body, excepting that of admixture with the substances of the body. And its uses are, to moisten, to cool, to cleanse, and also to nourish the parts with which it comes in contact. But it affords no nourishment of itself; it mixes with the blood, of which it forms a material part, and is the means of conveying the nourishment of the blood to every part of the system. After it has filled this office, and taken up impurities that are required to be removed, it is cast out of the system again, without undergoing any chemical change.
Man's body is to his Soul, in many respects, what a house is to its occupant. But how superior is the dwelling which God erected, to that which man has built. Reader, come out of yourself, and in imagination realise the abstraction of the Soul from the body. Make an effort of thought, and do not relinquish that effort, until you fancy that you see your image seated on a chair before you. And now proceed to ask yourself certain questions respecting your bodily tenement—questions which, perchance, have never occurred to you before; but which will impress themselves the more forcibly upon you, in proportion as you realise for a moment the idea of your Soul examining the body which it inhabits. There sits before you a form of exquisite proportions, with reference to the mode of life it has to pursue—the wants of the Soul for which it has to care, and which it has to guard, under the direction of that Soul, its owner and master.
Over the brows that mark the intellectual front of that due form, there fall the auburn locks of youth, or the grey hair of venerable age. Each of those hairs is curiously organised. If you take a branch of a tree, and cut it across, you will find curious markings caused by vessels of various structure, all necessary to the existence of the plant. In the centre will be found either a hollow tube, or a space occupied by a soft substance called pith. Each hair of your head is as curiously formed as the branch of a tree, and in a manner not dissimilar, though its parts are so minute that the unaided eye cannot discern them. Every hair has a root, just as a tree has, and through this root it receives its nourishment. As the vessel which feed a plant are always proportionate to the size of the plant itself, how fine must be those vessels which form the roots of the hair, being in proportion to the size of the hair, which is in itself so small that the eye cannot see its structure? The hair is, in fact, an animal plant, growing upon the body in much the same manner that plants grow upon the surface of the earth. But how does this hair grow? Not alone by the addition of matter at its roots, pushing up and elongating its stem: nourishment passes up through its whole length, and is deposited upon its end, just as the nourishment of a tree is deposited upon its extreme branches. If, after having your hair cut, you were to examine its ends by the microscope, you would discover the abrupt termination left by the scissors. But allow the hair to grow, and then examine it, and you will discover that it grows from its point which, in comparison with its former state, is perfect and fine. The reason why the beard is so hard is, that the ends of the hair are continually being shaved off. The hair of the beard, if allowed to grow, would become almost as soft as the hair of the head.
"The very hairs of your head are all numbered."—Matthew xi.
But why is man's head thus covered with hair? For precisely the same reason that a house is thatched—to keep the inmates warm. We might add, also, to give beauty to the edifice. But as beauty is a conventional quality—and if men were without it they would consider themselves quite as handsome as they do now—we will not enlarge upon the argument. Our bald-headed friends, too, might have reason to complain of such a partial hypothesis. The brain is the great organ upon which the health, the welfare, and the happiness of the system depends. The skull, therefore, may be regarded as analogous to the "strong box," the iron chest in which the merchant keeps his treasure. There is no point at which the brain can be touched to its injury, without first doing violence to the skull. Even the spinal cord runs down the back through a tunnel or tube, formed in a number of strong bones, so closely and firmly jointed together, that they are commonly termed "the back-bone."
Look at the eyebrows. What purpose do they fulfil? Precisely that of a shed, or arch placed over a window to shelter it from rain. But for the eyebrows the perspiration would frequently run from the brow into the eyes, and obscure the sight; a man walking in a shower of rain would scarcely be able to see; and a mariner in a storm would find a double difficulty in braving the tempest.
Now we come to the eye, which is the window of the Soul's abode. And what a window! how curiously constructed! how wisely guarded! In the eyelashes, as well as the eyebrows, we see the hair fulfilling a useful purpose, differing from any already described. The eyelashes serve to keep cold winds, dust, and too bright sun, from injuring or entering the windows of the body. When we walk against the east wind, we bring the tips of our eyelashes together, and in that way exclude the cold air from the surface of the eye; and in the same manner we exclude the dust and modify the light. The eyelashes, therefore, are like so many sentries, constantly moving to and fro, protecting a most important organ from injury. The eyelids are the shutters by which the windows are opened and closed. But they also cleanse the eye, keeping it bright and moist. There are, moreover, in the lids of each eye or window, little glands, or springs, by which a clear fluid is formed and supplied for cleansing the eye. The eye is placed in a socket of the skull, in which it has free motion, turning right or left, up or down, to serve the purpose of the inhabitant of the dwelling. Of the structure of the eye itself we will not say much, for the engravings will afford a clearer understanding than a lengthy written description. But we would have you examine the formation of the iris of the living eye, the ring which surrounds the pupil. Hold a light to it, and you will find that the iris will contract and diminish the pupil; withdraw the light, and the iris will relax, and the pupil expand, thus regulating the amount of light. The images of external objects are formed upon the retina of the eye, a thin membrane, spread out upon the extremity of a large nerve, which proceeds immediately to the brain, and forms the telegraphic cord by which information is given to the mind, of everything visible going on within the range of sight.
"Thou art of purer eyes than to behold evil, and canst not look on iniquity."—Habakkuk i.
Now, think for a few moments upon the wonderful structure of those windows of the body. Can you fancy, in the walls of your house, a window which protects itself, cleanses itself, and turns in any direction at the mere will of the tenant; and when that tenant is oppressed by excess of light, draws its own curtain, and gives him ease; and when he falls asleep, closes its own shutters, and protects itself from the cold and dust of night, and the instant he awakes in the morning, opens, cleanses itself with a fluid which it has prepared during the night, and kept in readiness; and repeats this routine of duty day after day for half a century, without becoming impaired? Such, nevertheless, is the wonderful structure of the window of the body—the eye.
In some scientific works that have recently been published, curious investigations have been made known. It has been shown that the eye is impressed momentarily, as a photographic plate is impressed by the rays of the sun. But the photography of the eye has this extraordinary quality—that one image passes away, and another takes its place immediately, without confusion or indistinctness. But the most wonderful assertion of all is, that under the excitement of memory these photographic images are restored; and that when, "in our mind's eye," we see the image of some dear departed friend, the retina really revives an image which once fell upon its sensitive surface, and which image has been stored up for many years in the sacred portfolio of its affections!
Another extraordinary assertion is one which comes supported by a degree of authenticity that entitles it to consideration. It is said that the eye of a dead man retains an impression of the last picture that fell upon the faithful retina. Dr. Sandford, of America, examined the eye of a man named Beardley, who had been murdered at Auburn, and he published in the Boston Atlas the following statement:—"At first we suggested the saturation of the eye in a weak solution of atrophine, which evidently produced an enlarged state of the pupil. On observing this, we touched the end of the optic nerve with the extract, when the eye instantly became protuberant. We now applied a powerful lens, and discovered in the pupil, the rude, worn-away figure of a man, with a light coat, beside whom was a round stone, standing or suspended in the air, with a small handle, stuck in the earth. The remainder was debris, evidently lost from the destruction of the optic nerve, and its separation from the mother brain. Had we performed the operation when the eye was entire in the socket, with all its powerful connection with the brain, there is not the least doubt but that we should have detected the last idea and impression made on the mind and eye of the unfortunate man. The picture would evidently be entire; and perhaps we should have had the contour, or better still, the exact figure of the murderer. The last impression on the brain before death is always more terrible from fear than any other cause, and figures impressed on the pupil more distinct, which we attribute to the largeness of the optic nerve, and its free communication with the brain." Whether the supposition, which seems to be supported by the experiment above detailed, be correct or not, it is in no sense more wonderful than the facts which are already known respecting this curious and perfect organ.
"Be not rash with thy mouth, and let not thine heart be hasty to utter anything before God: for God is in heaven, and thou upon earth; therefore let thy words be few."—Ecclesiastes v.
The nose is given us for two purposes—to enable us to respire and to smell. As odours arise from the surface of the earth, the cup or funnel of the nose is turned down to meet them. In the nostrils hair again serves a useful purpose. It not only warms the air which enters the nostrils, but it springs out from all sides, and forms an intersecting net, closing the nostrils against dust, and the intrusion of small insects. If by any means, as when taking a sharp sniff, foreign matters enter the nostrils, the nose is armed with a set of nerves which communicate the fact to certain muscles, and the organs of respiration unite with those muscles to expel the intruding substances. In this action, the diaphragm, or the muscle which divides the abdomen from the chest, is pressed down, the lungs are filled with air, the passage by which that air would otherwise escape through the mouth, is closed up, and then, all at once, with considerable force, the air is pressed through the nostrils, to free them from the annoying substance. So great is the force with which this action takes place, that the passage into the mouth is generally pushed open occasioning the person in whom the action takes place, to cry "'tsha!" and thus is formed what is termed a sneeze. As with the eye, so with the nose—innumerable nerves are distributed over the lining membrane, and these nerves are connected with larger nerves passing to the brain, through which everything relating to the sense of smell is communicated.
The nose acts like a custom-house officer to the system. It is highly sensitive to the odour of most poisonous substances. It readily detects hemlock, henbane, monk's hood, and the plants containing prussic acid. It recognises the fœted smell of drains, and warns us not to breathe the polluted air. The nose is so sensitive, that air containing a 200,000th part of bromine vapour will instantly be detected by it. It will recognise the 1,300,000th part of a grain of otto of roses, or the 13,000,000th part of a grain of musk! It tells us in the mornings that our bed-rooms are impure; it catches the first fragrance of the morning air, and conveys to us the invitation of the flowers to go forth into the fields, and inhale their sweet breath. To be "led by the nose," has hitherto been used as a phrase of reproach. But to have a good nose, and to follow its guidance, is one of the safest and shortest ways to the enjoyment of health.
The mouth answers the fourfold purpose of the organ of taste, of sound, of mastication, and of breathing. In all of these operations, except in breathing, the various parts of the mouth are engaged. In eating we use the lips, the tongue, and the teeth. The teeth serve the purpose of grinding the food, the tongue turns it during the process of grinding, and delivers it up to the throat for the purposes of the stomach, when sufficiently masticated. The lips serve to confine the food in the mouth, and assist in swallowing it, and there are glands underneath the tongue, and in the sides of the mouth, which pour in a fluid to moisten the food. And so watchful are those glands of their duty, that the mere imagination frequently causes them to act. Their fluid is required to modify the intensity of different flavours and condiments in which man, with his love of eating, will indulge. Thus, when we eat anything very acid, as a lemon, or anything very irritating, as Cayenne pepper, the effect thereof upon the sensitive nerves of the tongue is greatly modified by a free flow of saliva into the mouth. And if we merely fancy the taste of any such things, those glands are so watchful, that they will immediately pour out their fluid to mitigate the supposed effect.
"I say unto you, Swear not at all; neither by heaven, for it is God's throne; Nor by the earth; for it is his footstool."—Matthew v.
In speaking, we use the lips, the teeth, the tongue; and the chest supplies air, which, being controlled in its emission, by a delicate apparatus at the mouth of the wind-pipe, causes the various sounds which we have arranged into speech, and by which, under certain laws, we are enabled to understand each other's wants, participate in each other's emotions, express our loves, our hopes, our fears, and glean those facts, the accumulation of which constitutes knowledge, enhances the happiness of man, and elevates him, in its ultimate results above the lower creatures to which the blessing of speech is denied.
The curious structure of the tongue, and the organs of speech, would fill a very interesting volume. The tongue is unfortunately much abused, not only by those who utter foul words, and convert the blessing of speech, which should improve and refine, into a source of wicked and profane language; but it constantly remonstrates against the abuse of food, and the use of things which are not only unnecessary for the good of our bodies, but prejudicial to their health. When the body is sufficiently fed, the tongue ceases its relish, and derives no more satisfaction from eating: but man contrives a variety of inventions to whip the tongue up to an unnatural performance of its duty, and thus we not only over-eat, but eat things that have no more business in our stomachs, than have the stones that we walk upon. Can we wonder, then, that disease is so prevalent, and that death calls for many of us so soon.
That wonderful essence, the Soul of man, rises above all finite knowledge. Its wonders and powers will never, probably, be understood until when, in a future state of existence, the grandest of all mysteries shall be explained. When we talk of the brain, we speak of that which it is easy to comprehend as the organ, or the seat of the mind; when we speak of the mind, we have greater difficulty in comprehending the meaning of the term we employ; but when we speak of the Soul, we have reached a point which defies our understanding, because our knowledge is limited. The brain may be injured by a blow; the mind may be pained by a disagreeable sight, or offended by a harsh word; but the Soul can only be influenced secondarily through the mind, which is primarily affected by the organs of the material senses. Thus the happiness or the misery of the Soul depends to a very great extent upon the proper fulfilment of the duties of the senses, which are the servants of the Soul, over which the mind presides, as the steward who mediates between the employer and the employed.
The Ear, which is taught to delight in sweet sounds, and in pure language, is a better servant of the master Soul, than one which delights not in music, and which listens, with approbation or indifference, to the oaths of the profane. The Eye which rejoices in the beauties of nature, and in scenes of domestic happiness and love, is a more faithful servant than one that delights in witnessing scenes of revelry, dissipation, and strife. The Nose which esteems the sweet odour of flowers, or the life-giving freshness of the pure air, is more dutiful to his master than one that rejects not the polluted atmosphere of neglected dwellings. The Mouth which thirsts for morbid gratification of taste, is more worthless than one which is contented with wholesome viands, and ruled by the proper instincts of its duty. Who that can understand the wonderful structure of the tongue, and the complicated mechanism of the organs of speech and of hearing, could be found to take pleasure in the utterance of oaths, and of words of vulgar meaning? Were those beautiful cords that like threads of silk are woven into the muscular texture of the mouth, and along which the essence of life travels with the quickness of thought, to do the bidding of the will—were they given for no higher use than to sin against the God who gave them, and upon whose mercy their existence every moment depends?
"Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be."—James iii.
The actions of the senses must necessarily affect the mind, which is the head steward of the Soul; and the Soul becomes rich in goodness, or poor in sin, in proportion as the stewardship, held by his many servants, is rightly or wrong-fully fulfilled. As in an establishment where the servants are not properly directed and ruled, they often gain the ascendancy, and the master has no power over them, so with man, when he gives himself up to sensual indulgences. The Soul becomes the slave of the senses—the master is controlled by the servants.
With regard to the mechanism of motion, let us take the case of a man who is walking a crowded thoroughfare, and we shall see how active are all the servants of the Soul, under the influence of the mind. He walks along in a given direction. But for the act of volition in the mind, not a muscle would stir. The eye is watching his footsteps. There is a stone in his path, the eye informs the mind, the mind communicates with the brain, and the nerves stimulate the muscles of the leg to lift the foot a little higher, or turn it on one side, and the stone is avoided. The eye alights on a familiar face, and the mind remembers that the eye has seen that face before. The man goes on thinking of the circumstance under which he saw that person, and partially forgets his walk, and the direction of his steps. But the nerves of volition and motion unite to keep the muscles up to their work, and he walks on without having occasion to think continually, "I must continue walking." He has not to make an effort to lift his leg along between each interval of meditation; he walks and meditates the while. Presently a danger approaches him from behind. The eye sees it not—knows no more, in fact, than if it were dead. But the ear sounds the alarm, tells the man, by the rumbling of a wheel, and the tramp of horses' feet, that he is in danger; and then the nerves, putting forth their utmost strength, whip the muscles up to the quick performance of their duty; the man steps out of the way of danger, and is saved. He draws near to a sewer, which is vomiting forth its poisonous exhalations. The eye is again unconscious—it cannot see the poison lurking in the air. The ear, too, is helpless; it cannot bear witness to the presence of that enemy to life. But the nose detects the noxious agent, and then the eye points out the direction of the sewer, and guides his footsteps to a path where he may escape the injurious consequences. A clock strikes, the ear informs him that it is the hour of an appointment; the nerves stimulate the muscles again, and he is hastened onward. He does not know the residence of his friend, but his tongue asks for him, and his ear makes known the reply. He reaches the spot—sits—rests. The action of the muscles is stayed; the nerves are for a time at rest. The blood which had flown freely to feed the muscles while they were working, goes more steadily through the arteries and veins, and the lungs, which had been purifying the blood in its course, partake of the temporary rest.
"I am but a little child: I know not how to go out or come in."—I Kings iii.
Let us remember that there are two sets of muscles, acting in unison with each other, to produce the various motions; they are known by the general terms of flexors and extensors; the first enable us to bend the limbs, the other to bring the limbs back to their former position. The flexors enable us to close the hand, the extensors to open it again. The flexors enable us to raise the foot from the ground; the extensors set the foot down again in the place desired. Consider for a moment the nicety with which the powers of these muscles must be balanced, and the harmony which must subsist between them in their various operations. When we are closing the hand, if the extensor muscles did not gradually yield to the flexors—if they gave up their hold all at once, the hand, instead of closing with gentleness and ease, would be jerked together in a sudden and most uncomfortable manner. If, in such a case, you were to lay your hand with its back upon the table, and wish to close the hand, the fingers would fall down upon the palm suddenly, like the lid of a box. Again, consider how awkward it would be in such a case; our walk through the streets would become a series of jumps and jerks; when a man had raised his foot, after it had been jerked up, there it would stand fixed for a second before the opposite muscles could put on their power to draw it down again. This case is not at all suppositious: there is a derangement frequently observed in horses, in which one set of muscles becomes injured, and we may see horses suffering from this ailment, trotting along with one of their legs jerking up much higher than the others, and set down again with difficulty, just in the manner described.
It is also to be observed that very nice proportions must exist between the sizes of the muscles and the sizes of the bones. If this were not the case, our motions, instead of being firm and steady, would be all shaky and uncertain. In old persons the muscles become weak and relaxed; hence there is a tendency in the movements of the aged to fall, as it were, together; the head is no longer erect, the body bends, the knees totter, and the arms lean towards the body as for support.
In the child a somewhat similar state of things exists. The muscles have not been properly developed, nor have they been brought sufficiently under the controul of the nervous system. The child, therefore, totters and tumbles about, and it is not until it has stumbled and tumbled some hundreds of times in its little history, that the muscles have become strong enough to fulfil their office, or have been brought sufficiently under the controul of the nervous system, to perform well the various duties required from them.
In all these things, we recognise the perfection of the divine works. We are apt, too apt, to overlook this perfection, because it prevails in everything; but by speculating upon what inconveniences we might suffer, were not things ordained as they are, we obtain most convincing evidences of divine goodness and wisdom.
"Watchman, what of the night? The watchman said, The morning cometh, and also the night; if ye will enquire, enquire ye; return, come."—Isaiah xxi.
Having taken this view of the muscular system of the external man, let us turn our attention to the muscles of the internal organs. The muscles of which we have been speaking are called the voluntary muscles, because we have them under our own controul—they are subject to the influences of our will. But there is the other set of muscles. What are they? We talk of the beating, or of the palpitation, of the heart. But, what is it that causes the heart to beat? You cannot, if you wish it, make your heart beat more quickly or more slowly. Place your finger upon your pulse, and notice the degree of rapidity with which its pulsations follow. Now think that you should like to double the frequency of those pulsations. Say to the heart, with your inner voice, that you wish it to beat 120 times in a minute, instead of 60. It does not obey you; it does not appreciate your command. Now place your finger on the table, and your watch by the side of your hand, and tell your finger to beat 60 times in the minute, or 100 times, or 150 times, or 200 times, and the finger will obey you—because it is moved by muscles which are subject to the will, while the heart is composed of muscles which are not subject to the will. Why should this be? Why should man have the power to regulate his finger, and not to regulate his heart?
For the sustentation of our bodies it is needful that the blood should ever be in circulation. If the heart were to cease beating only for three or four minutes (perhaps less) life would be extinct. In this short time the whole framework of man, beautiful in its proportions, perfect in its parts, would pass into the state of dead matter, and would simply wait the decay that follows death. The eye would become dull and glazed, the lips would turn blue, the skin would acquire the coldness of clay—love, hope, joy, would all cease. The sweetest, the fondest ties would be broken. Flowers might bloom, and yield their fragrance, but they would be neither seen nor smelt; the sun might rise in its brightest splendour, yet the eye would not be sensitive to its rays; the rosy-cheeked child might climb the paternal knee; but there, stiff, cold, without joy, or pain, or emotion of any kind, unconscious as a block of marble, would sit the man whose heart for a few moments had ceased to beat.
How wise, then, and how good of God, that he has not placed this vital organ under our own care! How sudden would be our bereavements—how frequent our deaths, how sleepless our nights, and how anxious our days, if we had to keep our own hearts at work, and death the penalty of neglect.
And yet, before we were born, until we reach life's latest moment—through days of toil, and nights of rest—even in the moments of our deepest sin against the God who at the time is sustaining us, our hearts beat on, never stopping, never wearying, never asking rest.
This brings us to another reflection. Our arms get weary, our legs falter from fatigue, the mind itself becomes overtaxed, and all our senses fall to sleep. The eye sees not, the ear is deaf to sound, the sentinels that surround the body, the nerves of touch, are all asleep—you may place your hand upon the brow of the sleeping man, and he feels it not. Yet, unseen, unheard, without perceptible motion, or the slightest jar to mar the rest of the sleeper, the heart beats on, and on, and on. As his sleep deepens, the heart slackens its speed, that his rest may be the more sound. He has slept for eight hours, and the time approaches for his awakening. But is the heart weary—that heart which has toiled through the long and sluggard night? No! The moment the waking sleeper moves his arm, the heart is aware that a motion has been made, that effort and exercise are about to begin. The nerves are all arousing to action; the eyes turn in their sockets, the head moves upon the neck; the sleeper leaves his couch, and the legs are once more called upon to bear the weight of the body. Blood is the food of the eye, the food of the ear, of the foot, the hand, and every member of the frame. While they labour they must be fed—that is the condition of their life, the source of their strength. The heart, therefore, so far from seeking rest, is all fresh and vigorous for the labours of the day, and proceeds to discharge its duty so willingly, that we do not even know of the movements that are going on within us.
"Awake up, my glory; awake, psaltery and harp: I myself will awake early."—Psalm lvii.
Thus we have seen the difference between the voluntary and the involuntary muscles, and we have perceived the goodness of our Creator in not entrusting to our keeping the controul of an organ so vital to life, as the heart.
But the heart is not the only organ which thus works unseen and unfelt. There are the lungs and the muscles of the chest, the stomach, and other parts occupying the abdomen, together with all those muscular filaments which enter into the structure of the coats and valves of the blood-vessels, and which assist to propel the blood through the system. All these are at work at every moment of man's life; and yet, so perfect is this complicated machinery, that we really do not know, except by theory, what is going on within us.
During the time that the sleeper has been at rest, the stomach has been at work digesting the food which was last eaten. Then the stomach has passed the macerated food into the alimentary canal, the liver has poured out its secretion, and produced certain changes in the condition of the dissolved food: and the lacteals, of which there may be many thousands, perhaps millions, have been busy sucking up those portions of the food which they knew to be useful to the system, whilst they have rejected all those useless and noxious matters upon which the liver, like an officer of health, had set his mark, as unfitting for the public use. This busy life has gone on uninterruptedly; every member of that body, every worker in that wonderful factory, has been unremitting in his duty, and yet the owner, the master, has been asleep, and wakes up finding every bodily want supplied!
Notwithstanding that much has already been said of the wonders that pertain to the eye, it has not yet been considered as the seat of tears, those mute but eloquent utterers of the sorrows of the heart. Beautiful Tear! whether lingering upon the brink of the eyelid, or darting down the furrows of the care-worn cheek—thou art sublime in thy simplicity—great, because of thy modesty—strong, from thy very weakness. Offspring of sorrow! who will not own thy claim to sympathy? who can resist thy eloquence? who can deny mercy when thou pleadest?
Every tear represents some in-dwelling sorrow preying upon the mind and destroying its peace. The tear comes forth to declare the inward struggle, and to plead a truce against further strife. How meet that the eye should be the seat of tears—where they cannot occur unobserved, but, blending with the beauty of the eye itself, must command attention and sympathy!
Whenever we behold a tear, let our kindliest sympathies awake—let it have a sacred claim upon all that we can do to succour and comfort under affliction. What rivers of tears have flown, excited by the cruel and perverse ways of man! War has spread its carnage and desolation, and the eyes of widows and orphans have been suffused with tears! Intemperance has blighted the homes of millions, and weeping and wailing have been incessant! A thousand other evils which we may conquer have given birth to tears enough to constitute a flood—a great tide of grief. Suppose we prize this little philosophy, and each one determine never to excite a tear in another. Watching the eye as the telegraph of the mind within, let us observe it with anxious regard; and whether we are moved to complaint by the existence of supposed or real wrongs, let the indication of the coming tear be held as a sacred truce to unkindly feeling, and our efforts be devoted to the substitution of smiles for tears!
"Who is as the wise man? and who knoweth the interpretation of a thing? a man's wisdom maketh his face to shine, and the boldness of his face shall be changed."—Ecclesiastes viii.
There is only one other matter to which we think it necessary to allude, before we pass to the concluding section of our work. It has been said (162), that snow which is white, keeps the earth warm; that white as a colour is cool, and that black absorbs heat (230). These assertions may appear to be contradictory, and, taken in connection with the fact of the blackness of the skin of negroes in hot climates, may at a first glance be considered unsatisfactory. They are, however, perfectly reconcileable, and that too, without the slightest evasion of the real bearing of the asserted facts. White snow is warm on account of its texture, which, being woolly, forms a layer of non-conducting substance over the surface of the earth, and keeps in its warmth; white clothing, worn as a garment consisting of a thin material, is cool, because the white colour turns back the rays of the sun that fall upon it. Swansdown, although white, being a non-conductor, would be warm, because, though it would reflect the light and heat, it would confine and accumulate the heat of the body. The black skin of the negro is a living texture, and is not subject to the same laws that govern dead matter. The skin of the negro is largely provided with cells which secrete a fatty matter that acts as a non-conductor of the external heat, and also a much larger number of perspiratory glands than exist in the skins of Europeans. The perspiration cools the blood, and carries off the internal heat, while the oily matter gives a shining surface to the skin, and reflects the heat, to which the fatty matter presents itself as a non-conductor. We see, therefore, that there are two express provisions for the cooling of the negroes' skin, independent of the colour. The skin of the Esquimaux who inhabits a cold country is white, though it might be supposed that a black skin would best conduce to the warmth of his body. But the Esquimaux has, underneath his skin, a thick coating of fat, by which the internal heat of the body is prevented from escaping.
This resume of the subjects embodied in the form of question and answer in the previous pages, will serve to impress the more important truths upon the mind of the reader, while it has enabled us to fill up many omissions necessitated by the arbitrary form of catechetical composition.
"Ask now the beasts, and they shall teach thee; and the fowls of the air, and they shall tell thee."—Job xii.
CHAPTER LII.
1029. Why are there so many bodily forms in the animal creation?
Because the various creatures which God has created have different modes of life, and the forms of their bodies will be found to present a perfect adaptation to the lives allotted to them.
Because, also, the beauty of creation depends upon the variety of objects of which it consists. And the greatness of the Creator's power is shown by the diversity of ends accomplished by different means.
1030. Why are birds covered with feathers?
Because they require a high degree of warmth, on account of the activity of their muscles; but in providing that warmth it was necessary that their coats should be of the lightest material, so as not to impair their powers of flight; and feathers combine the highest warming power, with the least amount of weight.
1031. Why have ostriches small wings?
Because, having long legs, they do not require their wings for flight; they are merely used to steady their bodies while running.
1032. Why are ostrich feathers soft and downy?
Because, as the feathers are not employed for flight, the strength of the feather as constructed for flying is unnecessary, and the feathers therefore consist chiefly of a soft down.
1033. Why have water-birds feathers of a close and smooth texture?
Because such feathers keep the body of the bird warm and dry, by repelling the water from their surface. A bird could scarcely move through the water, with the downy feathers of the ostrich, because of the amount of water the down would absorb.
1034. Why is man born without a covering?
Because man is the only animal that can clothe itself. As in the various pursuits of life he wanders to every part of the globe, he can adapt himself to all climates and to any season.
"Who teacheth us more than the beasts of the earth, and maketh us wiser than the fowls of heaven?"—Job xxxv.
1035. Why do the furs of animals become thicker in the winter than in the summer?
Because the creator has thus provided for the preservation of the warmth of the animals during the cold months of winter.
1036. Why does a black down grow under the feathers of birds as winter approaches?
Because the down is a non-conductor of heat, and black the warmest colour. It is therefore best adapted to keep in their bodily warmth during the cold of winter.
1037. Why has man no external appendage to his mouth?
Because his hands serve all the purposes of gathering food, and conveying it to the mouth. Man's mouth is simply an opening; in other animals it is a projection.
1038. Why have dogs, and other carnivorous animals, long pointed teeth, projecting above the rest?
Because as they have not hands to seize and controul their food, the projecting teeth enable them to snap and hold the objects which they pursue for food.
1039. Why is the under jaw of the hog, shorter and smaller than the upper one?
Because the animal pierces the ground with its long snout, and then the small under jaw works freely in the furrow that has been opened, in quest of food.
1040. Why have birds hard beaks?
Because, having no teeth, the beak enables them to seize, hold, and divide their food.
1041. Why are the beaks of birds generally long and sharp?
Because the greater number of birds live by picking up small objects, such as worms, insects, seeds, &c. The sharp beak, therefore, serves as a fine pincers, enabling them to take hold of their food conveniently.
"As the fishes that are taken in an evil net, and as the birds that are caught in the snare; so are the sons of men snared in an evil time, when it falleth suddenly upon them."—Ecclesiastes ix.
1042. Why have snipes and woodcocks long tapering bills?
Because they live upon worms which they find in the soft mud of streams and marshy places; their long bills, therefore, enable them to dig down into the mud after their prey.
1043. Why have woodcocks, snipes, &c., nerves running down to the extremities of their bills?
Because, as they dig for their prey in the soft sand and mud, they cannot see the worms upon which they live. Nerves are, therefore, distributed to the very point of their bills (where, in other birds, nerves are entirely absent) to enable them to prehend their food.
Fig. 67.—SPOONBILL.
1044. Why have ducks and geese square-pointed bills?
Because they not only feed by dabbling in soft and muddy soil, but they consume a considerable quantity of green food, and their square bills enable them to crop off the blades of grass.
"Let the heaven and earth praise him, the seas, and everything that moveth therein."—Psalm lxix.
1045. Why has the spoon-bill a long expanded bill, lined internally with sharp muscular points?
Because the bird lives by suction, dipping its broad bill in search of aquatic worms, mollusks, insects and the roots of weeds. The bill forms a natural spoon, and the muscular points enable the bird to filter the mud, and to retain the nourishment which it finds.
1046. Why has the spoon-bill long legs?
Because it wades in marshy places to find its food. Its legs are therefore long, for the purpose of keeping its body out of the water, and above the smaller aquatic plants, while it searches for its prey.
1047. Why have the parrots, &c., crooked and hard bills?
Because they live upon nuts, the stones of fruit, and hard seeds. The shape of the bill, therefore, enables them to hold the nut or seed firmly, and the sharp point enables them to split or remove the husks.
1048. Why can a parrot move its upper as well as its lower bill?
Because by that means it is enabled to bring the nut or seed nearer the fulcrum, or joint of the jaw. It, therefore, acquires greater power, just as with a pair of nut-crackers we obtain increased power by setting the nut near to the joint.
1049. Why have animals with long necks large throats?
Animals that graze, or feed from the ground, generally have a more powerful muscular formation of the throat than those which feed in other positions, because a greater effort is required to force the food upward, than would be needed to convey it down.
1050. Why are the bones of birds hollow?
Because they are thereby rendered lighter, and do not interfere with the flight of the bird as they would do if they were solid. Greater strength is also obtained by the cylindrical form of the bone, and a larger surface afforded for the attachment of powerful muscles.
"And my hand hath found, as a nest, the riches of the people; and as one gathereth eggs that are left, have I gathered all the earth; and there was none that moved the whip, or opened the mouth, or peeped."—Isaiah x.
1051. Why do all birds lay eggs?
Because, to bear their young in any other manner, would encumber the body, and materially interfere with their powers of flight.
As soon as an egg becomes large and heavy enough to be cumbersome to the bird, it is removed from the body. A shell, impervious to air, protects the germ of life within, until from two to twenty eggs have accumulated, and then, although laid at different intervals, their incubation commences together, and the young birds are hatched at the same time.
CHAPTER LIII.
1052. Why have birds with long legs short tails?
Because the tails of birds are used to guide them through the air, by a kind of steerage. When birds with long legs take to flight, they throw their legs behind, and they then serve the same purpose as a tail.
Fig. 68.—PERCH.
The fins of fishes are to them, what wings and tails are to birds, enabling them to rise in the fluid in which they live by the reaction of the motions of the fins upon its substance.
"Speak to the earth, and it shall teach thee; and the fishes of the sea shall declare unto thee. Who knoweth not in all these that the hand of the Lord hath wrought this."—Job xii.
1054. Why are the fins of fishes proportionately so much smaller than the wings of birds?
Because there is less difference between the specific gravity of the body of a fish, and the water in which it moves, than between the body of a bird, and the air on which it flies. The fish, therefore does not require such an expanded surface to elevate or guide it.
Because scales, while they afford protection to the bodies of fish, are conveniently adapted to their motions; and as the scales present no surface to obstruct their passage through the water, as hair or feathers would do, they evidently form the best covering for the aquatic animal.
1056. Why do fishes float in streams (when they are not swimming) with their heads towards the stream?
Because they breathe by the transmission of water over the surface of their gills, the water entering at the mouth, and passing over the gills behind. When, therefore, they lie motionless with their heads to the stream, they are in that position which naturally assists their breathing process.
1057. Why have fishes air-bladders?
Because, as the density of water varies greatly at different depths, the enlargement or contraction of the bladder regulates the relation of the specific gravity of the body of the fish to that of the water in which it moves.
1058. Why have whales a very large development of oily matter about their heads?
Because their heads are thereby rendered the lighter part of their bodies, and a very slight exertion on the part of the animal will bring its head to the surface to breathe air, which it constantly requires.
1059. Why have birds that swim upon water web-feet?
Because the spreading out of the toes of the bird brings the membrane between the toes into the form of a fin, or water-wing, by striking which against the water, the bird propels itself along.
"And Jesus saith unto him, The foxes have holes, and the birds of the air have nests; but the son of man hath not where to lay his head."—Matthew xiii.
1060. Why have birds that swim and dive short legs?
Because long legs would greatly impede their motions in the water, by becoming repeatedly entangled in the weeds, and by striking against the bottom. Waders, however, require long legs because they have to move about through the tall vegetation of marshy borders.
Fig. 69.—STILT-PLOVER AND DUCK.
1061. Why have the feet of the heron, cormorant, &c., deep rough notches upon their under surface?
Because, as those birds live by catching fish, they are enabled by the notches in their feet, to hold the slippery creatures upon which they feed.
1062. Why have otters, seals, &c., web-feet?
Because, while the feet enable them to walk upon the land, they are equally effective in their action upon the water, and hence they are adapted to the amphibious nature of the animals to which they belong.
1063. Why do the external ears of animals of prey, such as cats, tigers, foxes, wolves, hyenas, &c., bend forward?
Because they collect the sounds that occur in the direction of the pursuit, and enable the animal to track its prey with greater certainty.
"Doth the hawk fly by thy wisdom, and stretch her wings toward the south? "Doth the eagle mount up at thy command, and make her nest on high?"
1064. Why do the ears of animals of flight, such as hares, rabbits, deer, &c., turn backward?
Because they thereby catch the sounds that give them warning of the approach of danger.
1065. Why has the stomach of the camel a number of distinct bags, like so many separate stomachs?
Because water is stored up in the separate chambers of the stomach, apart from the solid aliment, so that the animal can feed, without consuming all its drink. It is thereby able to retain water to satisfy its thirst while travelling across hot deserts, where no water could be obtained.
1066. Why do woodpeckers "tap" at old trees?
Because by boring through the decayed wood, with the sharp and hard bills with which they are provided, they get at the haunts of the insects upon which they feed.
1067. Why are woodpeckers' tongues about three times longer than their bills?
Because, if their bills were long, they would not bore the trees so efficiently; and when the trees are bored, and the insects alarmed, they endeavour to retreat into the hollows of the wood; but the long thin tongue of the woodpecker fixes them on its sharp horny point, and draws them into the mouth of the bird.
1068. Why have the Indian hogs large horns growing from their nostrils and turning back towards their eyes?
Because the horns serve as a defence to the eyes while the animal forces its way through the thick underwood in which it lives.
1069. Why have calves and lambs, and the young of horned cattle generally, no horns while they are young?
Because the presence of horns would interfere with the suckling of the young animal. When, however, it is able to feed itself by browsing, then the horns begin to grow.
"She dwelleth and abideth on the rock, upon the crag of the rock, and the strong place. "From thence she seeketh the prey, and her eyes behold afar off. Her young ones also suck up blood: and where the slain are, there is she."—Job xxxix.
1070. Why have infants no teeth?
Because the presence of teeth would interfere with their suckling, while the teeth would be of no service, until the child could take food requiring mastication.
1071. Why cannot flesh-eating animals live upon vegetables?
Because the gastric juice of a flesh-eating animal, being adapted to the duty which it has to perform, will not dissolve vegetable matter.
1072. Why have birds gizzards?
Because, having no teeth, the tough and fibrous gizzards are employed to grind the food preparatory to digestion.
1073. Why are small particles of sand, stone, &c., found in the gizzards of birds?
Because, by the presence of those rough particles, which become embedded in the substance of the gizzard, the food of the bird is more effectively ground.
When our fowls are abundantly supplied with meat, they soon fill their craw, but it does not immediately pass thence into the gizzard; it always enters in small quantities, in proportion to the progress of trituration, in like manner, as in a mill, a receiver is fixed above the two large stones which serve for grinding the corn, which receiver, although the corn be put into it by bushels, allows the grain to dribble only in small quantities into the central hole in the upper mill-stone.—Paley.
CHAPTER LIV.
1074. Why has the mole hard and flat feet, armed with sharp nails?
Because the animal is thereby enabled to burrow in the earth, in search for worms. Its feet are so many shovels.
1075. Why is the mole's fur exceedingly glossy and smooth?
Because its smoothness enables it to work under ground without the soil sticking to its coat, by which its progress would be impeded. From soils of all kinds, the little worker emerges shining and clean.
"I know all the fowls of the mountains, and the wild beasts are mine."—Psalm l.
What I have always most admired in the mole is its eyes. This animal occasionally visiting the surface, and wanting, for its safety and direction, to be informed when it does so, or when it approaches it, a perception of light was necessary. I do not know that the clearness of sight depends at all upon the size of the organ. What is gained by the largeness or prominence of the globe of the eye, is width in the field of vision. Such a capacity would be of no use to an animal which was to seek its food in the dark. The mole did not want to look about it; nor would a large advanced eye have been easily defended from the annoyance to which the life of the animal must constantly expose it. How indeed was the mole, working its way under ground, to guard its eyes at all? In order to meet this difficulty, the eyes are made scarcely larger than the head of a corking-pin; and these minute globules are sunk so deeply in the skull, and lie so sheltered within the velvet of its covering, as that any contraction of what may be called the eyebrows, not only closes up the apertures which lead to the eyes, but presents a cushion, as it were, to any sharp or protruding substance which might push against them. This aperture, even in its ordinary state, is like a pin-hole in a piece of velvet, scarcely pervious to loose particles of earth.—Paley.
Fig. 70.—ELEPHANTS DRINKING.
1076. Why has the elephant a short unbending neck?
Because the elephant's head is so heavy, that it could not have been supported at the end of a long neck (or lever), without a provision of immense muscular power.
"Be not afraid, ye beasts of the field: for the pastures of the wilderness do spring, for the tree beareth her fruit, the fig-tree and the vine do yield their strength."—Joel ii.
1077. Why has the elephant a trunk?
The trunk of an elephant serves as a substitute for a neck, enabling the animal to crop the branches of trees, or to raise water from the stream.
1078. Why do the hind legs of elephants bend forward?
Because the weight of the animal is so great, that when it lay down it would rise with great difficulty, if its legs bent outward, as do the legs of other animals. Being bent under the body, they have a greater power of pushing directly upward, when the powerful muscles of the thighs straighten them.
According to Cuvier, the number of muscles, in an elephant's trunk, amounts to forty thousand, all of which are under the will, and it is to these that the proboscis of this animal owes its flexibility. It can be protruded or contracted at pleasure, raised up or turned to either side, coiled round on itself or twined around any object. With this instrument the elephant collects the herbage on which he feeds and puts it into his mouth; with this he strips the trees of their branches, or grasps his enemy and dashes him to the ground. But this admirable organ is not only adapted for seizing or holding substances of magnitude; it is also capable of plucking a single leaf, or of picking up a straw from the floor. The orifices of the canals of the extremity are encircled by a projecting margin, produced anteriorly into a finger-like process endowed with a high degree of sensibility and exceedingly flexible. It is at once a finger for grasping and a feeler: the division between the two nasal orifices or their elevated sides serves as a point against which to press; and thus it can pick up or hold a small coin, a bit of biscuit, or any trifling thing with the greatest ease.—Knight's Animal Kingdom.
1079. Why have bats hooked claws in their wings?
Because bats are almost destitute of legs and feet; at least those organs are included in their wings. If they alight upon the ground, they have great difficulty in again taking to the wing, as they cannot run or spring to bring their wings in action upon the air. At the angle of each wing there is placed, therefore, a bony hook, by which the bat attaches itself to the sides of rocks, caves, and buildings, laying hold of crevices, joinings, chinks, &c.; and when it takes its flight, it unhooks itself, and its wings are at once free to strike the air.
1080. Why does the bat fly by night?
Because it lives chiefly upon moths, which are night-flying insects.
"So are the paths of all that forget God; and the hypocrite's hope shall perish: Whose hope shall be cut off, and whose trust shall be a spider's web."—Job viii.
1081. Why does the bat sleep during the winter?
Because, as the winter approaches, the moths and flying insects upon which it feeds, disappear. If, therefore, it did not sleep through the winter it must have starved.
Fig. 71.—BAT WITH HOOKED WINGS.
1082. Why has the spider the power of spinning a web?
Because, as it lives upon flies, but is deficient of the power of flying in pursuit of them, it has been endowed with an instinct to spread a snare to entrap them, and with the most wonderful machinery to give that instinct effect.
There are few things better suited to remove the disgust into which young people are betrayed on the view of some natural objects, than this of the spider. They will find that the most despised creature may become a subject of admiration, and be selected by the naturalist to exhibit the marvellous works of the creation. The terms given to these insects, lead us to expect interesting particulars concerning them, since they have been divided into vagrants, hunters, swimmers, and water spiders, sedentary, and mason-spiders; thus evincing a variety in their condition, activity, and mode of life; and we cannot be surprised to find them varying in the performance of their vital functions (as, for example, in their mode of breathing), as well as in their extremities and instruments. Of these instruments the most striking is the apparatus for spinning and weaving, by which they not only fabricate webs to entangle their prey, but form cells for their residence and concealment; sometimes living in the ground, sometimes under water, yet breathing the atmosphere. Corresponding with their very singular organisation are their instincts. We are familiar with the watchfulness and voracity of some spiders, when their prey is indicated by the vibration of the cords of their net-work. Others have the eye and disposition of the lynx or tiger, and after couching in concealment, leap upon their victims. Some conceal themselves under a silken hood or tube, six eyes only projecting. Some bore a hole in the earth, and line it as finely as if it were done with the trowel and mortar, and then hang it with delicate curtains. A very extraordinary degree of contrivance is exhibited in the trap-door spider. This door, from which it derives its name, has a frame and hinge on the mouth of the cell, and is so provided that the claw of the spider can lay hold of it, and whether she enters or goes out, says Mr. Kirby, the door shuts of itself. But the water-spider has a domicile more curious still: it is under water, with an opening at the lower part for her exit and entrance; and although this cell be under water, it contains air like a diving-bell, so that the spider breathes the atmosphere. The air is renewed in the cell in a manner not easily explained. The spider comes to the surface; a bubble of air is attracted to its body; with this air she descends, and gets under her cell, when the air is disengaged and rises into the cell; and thus, though under water, she lives in the air. There must be some peculiar property of the surface of this creature by which she can move in the water surrounded with an atmosphere, and live under the water breathing the air.
"The spider taketh hold with her hands, and is in king's palaces."—Proverbs xxx.
Fig. 72.—WEB OF THE GEOMETRICAL SPIDER.
The chief instrument by which the spider performs these wonders is the spinning apparatus. The matter from which the threads are spun is the liquid contained in cells; the ducts from these cells open upon little projecting teats, and the atmosphere has so immediate an effect upon this liquid, that upon exposure to it the secretion becomes a tough and strong thread. Twenty-four of these fine strands form together a thread of the thickness of that of the silk-worm. We are assured that there are three different sorts of material thus produced, which are indeed required for the various purposes to which they are applied—as, for example, to mix up with the earth to form the cells; to line these cells as with fine cotton; to make light and floating threads by which they may be conveyed through the air, as well as those meshes which are so geometrically and correctly formed to entrap their prey.—Note by Lord Brougham to Paley's Natural Theology.
"For every beast of the forest is mine, and the cattle upon a thousand hills."—Psalm l.
1083. Why have many insects a great number of eyes?
Because the orb of the eye is fixed; there is therefore placed over the eye a multiple-lens, which conducts light to the eye from every direction; so that the insect can see with a fixed eye as readily as it could have done with a movable one. As many as fourteen hundred eyes, or inlets of light, have been counted in the head of a drone-bee. The spider has eight eyes, mounted upon different parts of the head; two in front, two in the top of the head, and two on each side.
1084. Why have birds of prey no gizzards?
Because their food does not require to be ground prior to digestion, as does the food of grain-eating birds.
1085. Why have earth worms no feet?
Because the undulatory motion of their muscles serves them for fill the purposes of progression needed by their mode of life.
1086. Why have mussels strong tendinous threads proceeding from their shells?
Because as they live in places that are beaten by the surf of the sea, they moor their shells by those threads to rocks and timbers.
1087. Why have cockles stiff muscular tongues?
Because, having no threads to moor themselves, as the mussels have, they dig out with their tongues a shelter for themselves in the sand.
1088. Why do oxen, sheep, deer, &c., ruminate?
Because they have no front teeth in the upper jaw, the place of which is occupied by a hardened gum. The first process, therefore, consists simply of cropping their food, which is passed into the paunch, to be brought up again and ground by the back teeth when the cropping process is over.
Because, in a wild state, they are constantly exposed to the attacks of carnivorous beasts, and as the mastication of the large amount of vegetable food required for their sustenance would take a considerable time, they are provided with stomachs, by which they are enabled to fill their paunches quickly, and then, retiring to a place of safety, they bring their food up again, and chew it at leisure.
"A righteous man regardeth the life of his beast: but the tender mercies of the wicked are cruel."—Proverbs xii.
1089. Why can ruminating animals recover the food from their paunches?
Because they have a voluntary power over the muscles of the throat, by which they can bring up the food at will.
1090. Why can they keep the unchewed food in the paunch, from the "cud" they have chewed for nourishment?
Because their stomachs are divided into three chambers: 1, the paunch, where the unchewed food is stored; 2, the reticulum, where portions of the food are received from the paunch, and moistened and rolled into a "cud," to be sent up and chewed; and 3, the psalterium, which receives the masticated food, and continues the process of digestion.
In quadrupeds the deficiency of teeth is usually compensated by the faculty of rumination. The sheep, deer, and ox tribe, are without fore-teeth in the upper jaw. These ruminate. The horse and ass are furnished with teeth in the upper jaw, and do not ruminate. In the former class, the grass and hay descend into the stomachs nearly in the state in which they are cropped from the pasture, or gathered from the bundle. In the stomach, they are softened by the gastric juice, which in these animals is unusually copious. Thus softened and rendered tender, they are returned a second time to the action of the mouth, where the grinding teeth complete at their leisure the trituration which is necessary; but which was before left imperfect. I say, the trituration which is necessary; for it appears from experiments, that the gastric fluid of sheep, for example, has no effect in digesting plants, unless they have been previously masticated; that it only produces a slight maceration, nearly as common water would do in a like degree of heat; but that when once vegetables are reduced to pieces by mastication, the fluid then exerts upon them its specific operation. Its first effect is to soften them, and to destroy their natural consistency; it then goes on to dissolve them, not sparing even the toughest parts, such as the nerves of the leaves. I think it very probable, that the gratification also of the animal is renewed and prolonged by this faculty. Sheep, deer, and oxen, appear to be in a state of enjoyment whilst they are chewing the cud. It is then, perhaps, that they best relish their food.—Paley.
"I am like a pelican of the wilderness: I am like an owl of the desert. I watch, and am as a sparrow alone upon the house top."—Psalm cii.
CHAPTER LV.
1091. Why do quadrupeds that are vegetable eaters feed so continually?
Because their food contains but a small proportion of nutrition, so that it is necessary to digest a large quantity to obtain sufficient nourishment.
1092. Why do flesh eating animals satisfy themselves with a rapid meal?
Because the food which they eat is rich in nutritious matter, and more readily digestible than vegetable food; it does not therefore, require the same amount of grinding with the teeth.
Fig. 73.—PELICAN WITH DILATED POUCH.
1093. Why has the pelican a large pouch under its bill?
Because it subsists upon fish, generally of the smaller kind, and uses its pouch as a net for catching them; the pouch also serves as a paunch, in which the fish are stored, until the bird ceases from the exertion of fishing, and takes its meal at leisure.
"And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that it was good."—Genesis i.
In their wild state they hover and wheel over the surface of the water, watching the shoals of fish beneath, and suddenly sweeping down, bury themselves in the foaming waves; rising immediately from the water by their own buoyancy, up they soar, the pouch laden with the fish scooped up during their momentary submersion. The number of fish the pouch of this species will contain may be easily imagined when we state that it is so dilatable as to be capable of containing two gallons of water; yet the bird has the power of contracting this membranous expansion, by wrinkling it up under the lower mandible, until it is scarcely to be seen. In shallow inlets, which the pelicans often frequent, it nets its prey with great adroitness.
The pelican chooses remote and solitary islands, isolated rocks in the sea, the borders of lakes and rivers, as its breeding place. The nest, placed on the ground, is made of coarse grasses, and the eggs, which are white, are two or three in number. While the female is incubating, the male brings fish to her in his pouch, and the young, when hatched, are assiduously attended by the parents, who feed them by pressing the pouch against the breast, so as to transfer the fish from the former into the throats of the young. This action has doubtless given origin to the old fable of the pelican feeding its young with blood drawn from its own breast.—Knight's Animal Kingdom.
1094. Why do the smaller animals breed more abundantly than the larger ones?
Because the smaller ones are designed to be the food of the larger ones, and are therefore created in numbers adapted to that end. An elephant produces but one calf; the whale but one young one; a butterfly lays six hundred eggs; silk-worms lay from 1,000 to 2,000 eggs; the wasp, 5,000; the ant, 4,000 to 5,000; the queen bee, 5,000 to 6,000, or 40,000 to 50,000 in a season; and a species of white ant (termes fatalis) produces 86,400 eggs in a day. Birds of prey seldom produce more than two eggs; the sparrow and duck tribe frequently sit upon a dozen; in rivers there prevail a thousand minnows for one pike; and in the sea, a million of herrings for a single shark; while of the animalcules upon which the whale subsists, there must exist hundreds of millions for one whale.
1095. Why has the whale feathery-like laminæ of whale-bone extending from its jaws?
Because these feathery bones, lying side by side, form a sieve, or strainer, for the large volumes of water which the whale receives into its mouth, drawing off therefrom millions of small animals, which form a jelly-like mass upon which the whale feeds. A whale has been known to weigh as much as 249 tons, and its blubber yielded 4,000 gallons of oil. How many millions of living creatures must have gone to make up that enormous mass of animal matter!
"Hast thou given the horse strength? hast thou clothed his neck with thunder? * * He paveth the valley, and rejoiceth in his strength: he goeth on to meet the armed men."—Job xxxix.
1096. Why have cats, and various other animals, whiskers?
The whiskers of cats, and of the cat tribe, are exceedingly sensitive, enabling them, when seizing their prey in the dark, to feel its position most acutely. These hairs are supplied, through their roots, with branches of the same nerves that give sensibility to the lips, and that in insects supply their "feelers."
1097. Why has the horse a smaller stomach proportionately than other animals?
Because the horse was created for speed. Had he the ruminating stomach of the ox, he would be quite unfitted for the labour which he now so admirably performs.
1098. Why has the horse no gall-bladder?
Because the rapid digestion of the horse, by which its fitness for speed is greatly increased, does not require the storing up of the bile as in other animals in which the digestive process is a slower operation.
1099. Why do certain butterflies lay their eggs upon cabbage leaves?
Because the cabbage leaves are the food of the young caterpillars; and although the butterfly does not subsist herself upon the leaf, she knows by instinct that the leaf will afford food to her future young; she therefore lays her eggs where her young ones will find food.
This explanation applies to many insects that lay their eggs upon other plants.
1100. Why have insects long projections from their heads, like horns or feathers?
Because those organs (the antennæ), are those through which come insects hear and others feel; and the projecting of these antennæ from their bodies probably enables them to hear or feel more acutely while their wings are in motion, without the interference of the vibrations of their wings.
"My son, eat thou honey, because it is good; and the honey-comb, which is sweet to thy taste."—Proverbs xxiv.
Because they gather and store up honey which would constantly attract other insects, and the bees would be robbed of their food but for the sting, which is given to them for protection.
1102. Why have flies fine hairs growing at the extremities of their legs?
Because they require to cleanse their bodies and wings, and to free them from particles of dust. And as they cannot turn their heads for this purpose, they have hairy feet, which serve as brushes, by which any part of their bodies can be reached and cleaned.
CHAPTER LVI.
1103. Why when the perfume of flowers is unusually perceptible may wet weather be anticipated?
Because when the air is damp it conveys the odours of flowers more effectively than it does when dry.
1104. Why when swallows fly low may wet weather be expected?
Because the insects which the swallows pursue in their flight are flying low, to escape the moisture of the upper regions of the atmosphere.
1105. Why do ducks and geese go to the water, and dash it over their backs on the approach of rain?
Because by wetting the outer coat of their feathers before the rain falls, by sudden dashes of water over the surface, they prevent the drops of rain from penetrating to their bodies through the open and dry feathers.
1106. Why do horses and cattle stretch out their necks and snuff the air on the approach of rain?
Because they smell the fragrant perfume which is diffused in the air by its increasing moistness.
"I will remember the works of the Lord: Surely I will remember thy wonders of old."—Psalm lxxvii.
1107. Why may change of weather be anticipated when domestic animals are restless?
Because their skins are exceedingly sensitive to atmospheric influences, and they are oppressed and irritated by the changing condition of the atmosphere.
1108. Why may fine weather be expected when spiders are seen busily constructing their webs?
Because those insects are highly sensitive to the state of the atmosphere, and when it is setting fine they build their webs, because they know instinctively that flies will be abroad.
1109. Why is wet weather to be expected when spiders hide?
Because it shows that they are aware that the state of the atmosphere does not favour the flight of insects.
1110. Why if gnats fly in large numbers may fine weather be expected?
Because it shows that they feel the state of the atmosphere to be favourable, which induces them all to leave their places of shelter.
1111. Why if owls scream during foul weather, will it change to fine?
Because the birds are pleasurably excited by a favourable change in the atmosphere.
1112. Why is it said that the moping of the owl foretells death?
Because owls scream when the weather is on the change; and when a patient is lingering on a death bed, the alteration in the state of the atmosphere frequently induces death, because the faint and expiring flame of life has not strength enough to adapt itself to the change.
1113. Why may wet weather be expected when spiders break off their webs, and remove them?
Because the insects, anticipating the approach of rain, remove their webs for preservation.
"There shall the great owl make her nest, and lay, and hatch, and gather under her shadow: there shall the vultures also be gathered, every one with her mate."—Isaiah xxxiv.
1114. Why may we expect a continuance of fine weather when bees wander far from their hives?
Because the bees feel instinctively that from the state of the atmosphere they may wander far in search of honey, without the danger of being overtaken by rain.
1115. Why if people feel their corns ache, and their bones rheumatic, may rain be expected?
Because the dampness of the atmosphere affects its pressure upon the body, and causes a temporary disturbance of the system. All general disturbances of the body, manifest themselves in those parts which are in a morbid state—as in a corn, a rheumatic bone, or a decayed tooth.
1116. Why if various flowers close may rain be expected?
Because plants are highly sensitive to atmospheric changes, and close their petals to protect their stamens.
1117. Why when moles throw up their hills may rain be expected?
Because the moles know instinctively, that on the approach of wet, worms move in the ground; the moles therefore become active, and form their hills.
1118. Why is a magpie, when seen alone, said to foretell bad weather?
Because magpies generally fly in company; but on the approach of wet or cold, one remains in the nest to take care of the young, while the other one wanders alone in search of food.
1119. Why do sea-gulls appear numerous in fine weather?
Because the fishes swim near to the surface of the sea, and the birds assemble over the sea to catch the fish, instead of sitting on rocks, or wading on the shore.
1120. Why do sea-gulls fly over the land, on the approach of stormy weather?
Because in stormy weather they cannot catch fish; and the earth-worms come up on the land when the rain falls.
"And I said, Oh, that I had wings like a dove! for then would I fly away, and be at rest."—Psalm lv.
1121. Why if birds cease to sing, may wet, and probably thunder, be expected.?
Because birds are depressed by an unfavourable change in the atmosphere, and lose those joyful spirits which give rise to their songs.
1122. Why if cattle run around in meadows, may thunder be expected?
Because the electrical state of the atmosphere has the effect of making them feel uneasy and irritable, and they chase each other about to get rid of the irritability.
1123. Why if birds of passage arrive early, may severe weather be expected?
Because it shows that the indications of unfavourable weather have set in, in the latitudes from which the birds come, and that they have taken an early flight to escape it.
1124. Why if the webs of the gossamer spider fly about in the autumn, may east winds be anticipated?
Because an east wind is a dry and dense wind, and suitable to the flight of the gossamer spider; the spider feeling instinctively the dryness of the air, throws out its web, and finds it more than usually buoyant upon the dense air.
The observation of the changing phenomena which attend the various states of the weather is a very interesting study, though no general rules can be laid down that can be relied upon, because there are modifying circumstances which influence the weather in various localities and climates. To observe weather indications accurately, no phenomenon should be taken alone, but several should be regarded together. The character and the duration of the weather of the preceding days, the direction of the wind, the forms of the clouds, the indications of the barometer, the rise or fall of the thermometer, and the instinctive forewarnings of birds, beasts, insects, and flowers, should all be taken into account. Although no direct material advantages attend such a study, it induces a habit of observation, and develops the inductive faculty of the mind, which, when applied to more significant things, may trace important effects to their greater causes.
"Go to the ant, thou sluggard; consider her ways, and be wise."—Prov. vi.
CHAPTER LVII.
1125. Why can gossamer spiders float through the air?
Because, having no wings, and being deficient in the active muscular powers of other spiders, they have been endowed with the power of spinning a web which is so light that it floats in the air, and bears the body of the gossamer spider from place to place. Each web acts as a balloon, and the spider attached thereto is a little aeronaut.
1126. Why do crickets make a peculiar chirping sound?
Because they have hard wing cases, by the friction of the edges of which they cause their peculiar noise, to make known to each other where they are, in the dark crevices in which they hide.
Fig. 74.—GLOW-WORM USING HIS BRUSH.
1127. Why has the glow-worm a brush attached to its tail?
Because it is necessary to keep its back very clean, that the light which its body emits may not be dimmed.
1128. Why does the glow-worm emit a light?
Because the female glow-worm is without wings, but the male is a winged insect. The female, therefore, is endowed with the power of displaying a phosphorescent light. The light is only visible by night, but it is, nevertheless, beautifully adapted for the purpose stated, because the male is a night-flying insect, and never ventures abroad by day.
"They that go down to the sea in great ships, that do business in great waters these see the works of the Lord, and his wonders in the deep."—Psalm cvii.
There exists some difference of opinion between naturalists upon the uses of the light of a glow-worm; there are some who doubt that it is exhibited to attract the flying insect. The objectors, however, offer no explanation of the luminous properties of the worm. Sir Charles Bell says the preponderance of the argument is decidedly in favour of the explanation we have given.
1129. Why does not the iris of the fish's eye contract?
Because the diminished light in water is never too strong for the retina.
1130. Why is the eye of the eel covered with a transparent horny covering?
Because, as the eel lives in holes, and pushes its head into mud, and under stones, &c., it needed such a covering to defend the eye.
1131. Why is the whale provided with an eye, having remarkably thick and strong coats?
Because, when he is attacked by the sword-fish and the shark, he is almost helpless against his enemies, as they fix themselves upon his huge carcase. He therefore dives with them down to a depth where the pressure of the water is so great that they cannot bear it. The eye of the whale is expressly organised to bear the immense pressure of extreme ocean depths, without impairing the sight.
1132. Why have fishes no eyelids?
Because the water in which they swim keeps their eyes moist. Eyelids would therefore be useless to them.
1133. Why have fishes the power of giving their eye-balls very sudden motion?
Because, having no eyelids (such organs being unnecessary to keep their eyes moist), they still need the power of freeing their eyes from the contact of foreign matters; and this is secured to them by the power they have of giving the eyeball a very rapid motion, which causes reaction in the fluid surrounding it, and sweeps the surface.
This motion may frequently be seen in the eyes of fishes, in glass globes.
"And God made the beast of the earth after his kind, and cattle after their kind, and everything that creepeth upon the earth after his kind: and God saw that it was good."—Genesis i.
1134. Why is the lachrymal secretion of the horse's eye thick and glutinous?
Because, as his eye is large, and constantly exposed to dust on journeys, it is provided with a viscid secretion, which cleanses the eye, and more instantly and securely removes the dust, than a watery secretion would.
1135. Why does the lower bill of the sea-crow project beyond the upper one?
Because the bird obtains his food by skimming along the water, into which he dips his bill, and lifts his food out.
1136. Why do the mandibles of the cross-bill overlap each other?
Because the bird requires a peculiar bill, to enable it to split seeds into halves, and to tear the open cones of the fir-tree.
1137. Why are the tails of fishes so much larger than their fins?
Because their tails are their chief instruments of motion, while their fins are employed simply to direct their progress, and steady their movements.
1138. Why have oxen, and other quadrupeds a tough ligament called the "pax-wax," running from their backs to their heads?
Because their heads are of considerable weight; and having frequent occasion to lift them, they are provided with an elastic ligament, which is fastened at the middle of their backs, while its other extremity is attached to the head. This enables them to raise their heads easily; otherwise the effort to do so would be a work of great labour. To the horse, the pax-wax acts as a natural bearing-rein, assisting it to hold its head in that position which adds to the grace and beauty of the animal.
In carving beef, this ligament may be seen passing along the vertebræ of the neck, the chuck, and the fore ribs.
"He shall feed his flock like a shepherd; he shall gather the lambs with his arm, and carry them in his bosom, and shall gently lead those that are with young."—Isaiah xl.
1139. Why have the females of the kangaroo and opossum tribes pouches, or pockets, formed in the skin of their breasts for the reception of their young?
Because their young ones are remarkably small and helpless; in fact, more so than those of any other animal of equal proportions. Besides which, the full grown animals have very long hind-legs, and they progress by a series of extraordinary leaps. It would consequently be impossible for their helpless young ones to follow them: God has therefore given to female kangaroos and opossums curious pockets, formed out of their own skin, in which they place their little young ones, and bear them through their surprising leaps with the greatest ease and safety.
CHAPTER LVIII.
1140. What is the difference between an animal, a plant, and a mineral?
The great naturalist, Linnæus, used to say that animals grow, live, and feel; plants grow and live; and minerals grow.
Animals are here defined to enjoy three conditions of existence; plants two conditions; and minerals one condition.
This definition has, in latter days, been held to be unsatisfactory, since there are a few plants that are supposed to feel, and a few animals that are supposed to have even less feeling than the sensitive plants alluded to.
The concise definition by Linnæus, nevertheless, is true, as far as regards a vast majority of the bodies constituting the three great kingdoms of nature. And it may be sufficient to say that
Animals—grow, live, feel, and move.
Plants—grow and live.
Minerals—grow, by the addition of particles of inorganic matter.
If we now state the few exceptions that are admitted to this definition, we shall bring the explanation as near to the truth, as the present state of knowledge will permit.
"And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree, yielding seed; to you it shall be for meat."—Genesis i.
1141. Why is it understood that some plants feel?
Because the sensitive plant closes its leaves on being touched; the Venus's fly trap closes its leaves upon flies that alight upon them; others close upon the approach of rain, and at sunset, and open at sunrise, and turn towards the sun during its daily transit.
1142. Why is it understood that some plants move?
Because certain sea-weeds throw off undeveloped young plants, which move through the water by the aid of fine cilia, or muscular hairs, until they find a suitable place upon which to attach themselves.
The roots of plants will penetrate through the ground in the direction of water, and of favourable soil.
1143. Of what elementary substances are plants composed?
Of carbon, oxygen, hydrogen, and nitrogen.
1144. Whence do plants derive those substances?
From the air, the earth, and water.
1145. How do plants obtain carbon?
They obtain it chiefly from the air, in the form of carbonic acid gas. The carbon, of the carbonic acid gas, which is thrown out by the breath of animals, and by other processes in nature, is absorbed by the leaves of plants, and the oxygen which had united with the carbon to form the carbonic acid gas, is again set free for the use of animals.
1146. How do plants obtain oxygen?
They obtain it from the atmospheric air. But as they do not require a large amount of oxygen for their own use, they throw off the amount which is in excess, after having separated it from the other elements with which it was combined when taken up by them. From the humble blade of grass, to the stately tree of the forest, plants operate to purify the air, and to correct and counteract the corruption of the air, by the myriads of animals inhabiting the earth.
It has been generally stated that plants in rooms purify the air by absorbing carbonic acid by day, and releasing a part of the oxygen; but that, as the presence of light is necessary to produce this action, they do not restore oxygen to the air, by night, but, on the contrary, give off carbonic acid gas. Therefore it has been stated that plants in rooms by night are unhealthy. Mr. Robert Hunt, one of the ablest chemists of the present time, makes the following remarks upon this subject in his "Poetry of Science:"—
"The heavens declare the glory of God: and the firmament showeth his handy work. Day unto day uttereth speech, and night unto night showeth knowledge."—Psalm xix.
"The power of decomposing carbonic acid is a vital function which belongs to the leaves and bark. It has been stated, on the authority of Leibig, that during the night the plant acts only as a mere bundle of fibres—that it allows of the circulation of carbonic acid and its evaporation, unchanged. In his eagerness to support his chemical hypothesis of respiration, the able chemist neglected to enquire if this was absolutely correct. The healthy plant never ceases to decompose carbonic acid during one moment of its existence; but during the night, when the excitement of light is removed, and the plant reposes, its vital powers are at their minimum of action, and a much less quantity is decomposed than when a stimulating sun, by the action of its rays, is compelling the exertion of every vital function."
In hot, swampy countries, where vegetation is very rapid, and the soil loaded with decomposing carbonic matter, the plants absorb more carbonic acid than they require, and they then evolve carbonic acid gas from their leaves. Hence such climates as the West Indies are injurious to life, though favourable to vegetation.
1147. How do plants obtain hydrogen?
They obtain hydrogen in combination with oxygen in water, and with nitrogen, in the form of ammonia, as which it exists in animal manures.
1148. How do plants obtain nitrogen?
From the atmospheric air, and from the soil, in which it is combined with other elements.
1149. How do plants apply these elements to the formation of their own structures?
When those substances which form the food of plants are absorbed, either by their leaves or their roots, they are converted, with the aid of water, into a nutritive sap, which answers the same purposes in plants as blood does in animals.
1150. How is the nutritive sap applied to the growth and enlargement of the plant?
Every seed contains a small amount of nutrition, sufficient for the sustentation of the germ of the plant, until those vessels are formed, by which the nutritive elements can be absorbed and used for the further development of the living structure.
The earth, penetrated by the sun's rays, warms the sleeping germ, and quickens it into life. For a short time the germ lives upon the seed, which, moistened and warmed by the soil, yields a kind of glutinous sap, out of which the first members of the plant are formed. And then the tender leaf, looking up to the sky, and the slender rootlet penetrating the soil, begin to draw their sustenance from the vast stores of nature.
"He causeth the grass to grow for the cattle, and herb for the service of man: that he may bring forth food out of the earth."—Psalm civ.
1151. Of what do vegetable structures consist?
Of membranes, or thin tissues, which, being variously arranged, form cells, tubes, air passages, &c. Of fibres, which form a stronger kind of membrane, and which is variously applied to the production of the organs of the plants. And of organs, formed by those elementary substances, by which the plants absorb, secrete, and grow, and fulfil the conditions of their existence.
1152. Why are seeds generally enveloped in hard cases?
Because the covering of the seed, like the shell of an egg, is designed to preserve the germ within from the influence of external agencies, until the time for development has arrived, and the conditions of germination are fulfilled.
1153. Why does a seed throw out a root, before it forms a leaf?
Because moisture, which the root absorbs from the earth, is necessary to enable the germ to use the nutrition which the seed itself contains, and out of which the leaf must be eliminated. Moisture forms a kind of gluten, in which the starch of the seed is dissolved, and converted into sugar, the sugar into carbonaceous sap, and the sap into cellular tissue and woody fibre, as the leaves present themselves to the influence of the air and light.
Because, as soon as membranes and vessels are organised in the young germ, the nutritive fluid, formed by its first organs, begins to move through the fine structures, and from that time the plant commences to incorporate with its own substance the elements with which it is surrounded, that are suitable to its development.
"Can the rush grow up without mire? can the flag grow without water? Whilst it is yet in his greenness, and not cut down, it withereth before any other herb."—Job viii.
CHAPTER LIX.
1155. Why, if we break the stem of a hyacinth, do we see a glutinous fluid exude?
Because, by breaking the stem, we rupture the vessels of the plant, and cause the nutritive fluid to escape. The sap of the plant is analogous to the blood of man, and the vessels, to the arteries and veins of the animal body.
1156. Why, if we split the petal of a tulip, do we see cells containing matter of various colours?
Because, by splitting the petal of the flower, we disclose the anatomy of its structure, and bring to view those cells, or organs, of the vegetable body, by which the different colouring matters are secreted.
1157. Why, if we break a pea-shell across, do we discover a transparent membrane which may be removed from the green cells underneath?
Because we separate from the cellular, or fleshy part of the shell, the membrane, which forms the epidermis, and answers to the skin of the animal body.
1158. Why, if we cut through a cabbage stump, do we find an outer coat of woody fibre, and an inner substance of cellular matter?
Because the woody fibre forms a kind of skeleton, which supports the internal stricture of the plant, and gives form and character to its organisation. The woody fibre of plants is analogous to the bony structure of animal bodies.
1159. Why, if we cut across the stem of a plant do we see numerous tubes arranged in parallel lines?
Because we thereby bring to view the vessels formed by the membranes and fibres of the vegetable body, for the transmission of the fluids, by which the structure is sustained.
"It was planted in a good soil by great waters, that it might bring forth branches, and that it might bear fruit, that it might be a goodly vine."—Ezekiel xvii.
Skeleton leaves, and seed vessels of plants, form exceedingly interesting objects, and serve to illustrate the wonderful structure of plants. With patience and care, they may be produced by any person, and will afford an interesting occupation. The leaves should be gathered when they are in perfection—that is, when some of the earliest leaves begin to fall from the trees. Select perfect leaves, taking care that they are not broken, or injured by insects. Lay them in pans of rain water, and expose them to the air to undergo decomposition. Renew the water from time to time, taking care not to damage the leaves. They need not be examined more than once a week, and then only to see that the water is sufficient to cover them. Give them sufficient time for their soft parts to become decomposed, then take them out, and laying them on a white plate with a little water, wash away carefully, with a camel-hair pencil, the green matter that clings to the fibres. The chief requirement is patience on the part of the operator, to allow the leaves and seed vessels sufficient time to decompose. Some leaves will take a few weeks, and others a few months, but a large panful may be put to decompose at the same time, and there will always be some ready for the process of cleansing. When they are thoroughly cleaned, they should be bleached, by steeping for a short time in a weak solution of chloride of lime. They should then be dried, and either pressed flat, or arranged in bouquets for preservation under glass shades. The result will amply reward the perseverance of the operator.
1160. Why are clayey soils unfavourable to vegetation?
Because the soil is too close and adhesive to allow of the free passage of air or water to the roots of the plants; it also obstructs the expansion of the fibres of the roots.
1161. Why are sandy soils unfavourable to vegetation?
Because they consist of particles that have too little adhesion to each other; they do not retain sufficient moisture for the nourishment of the plants; and they allow too much solar heat to pass to the roots.
1162. Why are chalk soils unfavourable to vegetation?
Because they do not absorb the solar rays, and are therefore cold to the roots of plants.
1163. Why are mixed soils favourable to vegetation?
Because they contain the elements of nutrition essential to the development of the vegetables, and the plants absorb from them those constituents which are necessary to their growth.
1164. Why do farmers sow different crops in rotation?
Because every plant takes something from the soil, and gives something back; but all kinds of plants do not absorb nor restore the elements in the same proportions. Therefore a succession of crops of one kind would soon impoverish the soil; but a succession of crops of different kinds will compensate the soil, in some degree, for the nourishment withdrawn.
"He watereth the hills from his chambers; the earth is satisfied with the fruit of thy works."—Psalm civ.
1165. Why do farmers manure their lands?
Because, as soils vary, and crops impoverish the soils, the farmer employs manure to restore fertility, and to adapt the soils to the wants of the plants he desires to cultivate.
It is remarkable that Nature herself points out to man the necessity for changing the succession of vegetable growths.
When plants have exhausted the soil upon which they grow, they will push their roots far in search of sustenance, and in time migrate to a new soil, while other plants will spring up and thrive upon the area vacated. When a forest in North America is destroyed by fire, the trees that grow afterwards are unlike those that the fire consumed, and evidently arise from seeds that have long lain buried in the earth, waiting the time when the ascendancy of the reigning order of plants should cease.
1166. Why are grasses so widely diffused throughout nature?
Because they form the food of a very large portion of the animal kingdom. They have therefore been abundantly provided. No spot of earth is allowed to remain idle long. When the foot of man ceases to tread down the path, grass immediately begins to appear; and by its universality and the hardihood of its nature, it clothes the earth as with a carpet.
Many grasses, whose leaves are so dry and withered that the plants appear dead, revive and renew their existence in the spring by pushing forth new leaves from the bosom of the former ones.—Withering's Botany.
Grasses are Nature's care. With these she clothes the earth; with these she sustains its inhabitants. Cattle feed upon their leaves; birds upon their smaller seeds; men upon the larger; for, few readers need be told that the plants which produce our bread-corn, belong to this class. In those tribes which are more generally considered as grasses, their extraordinary means and powers of preservation and increase, their hardiness, their almost unconquerable disposition to spread, their faculties of reviviscence, coincide with the intention of nature concerning them. They thrive under a treatment by which other plants are destroyed. The more their leaves are consumed, the more their roots increase. The more they are trampled upon, the thicker they grow. Many of the seemingly dry and dead leaves of grasses revive, and renew their verdure in the spring. In lofty mountains, where the summer heats are not sufficient to ripen the seeds, grasses abound which are viviparous, and consequently able to propagate themselves without seed. It is an observation, likewise, which has often been made, that herbivorous animals attach themselves to the leaves of grasses; and, if at liberty in their pastures to range and choose, leave untouched the straws which support the flowers.—Paley.
"For the earth bringeth forth fruit of herself; first the blade, then the ear, after that the full ear in the corn."—Mark v.
CHAPTER LX.
1167. Why do some plants droop, and turn to the earth after sunset?
Because, when the warmth of the son's rays is withdrawn, they turn downwards, and receive the warmth of the earth by radiation.
1167. Why does the young ear of corn first appear enfolded in two green leaves?
Because the light and air would act too powerfully for the young ear; two leaves therefore join, and embrace the ear, and protect it until it has acquired strength, when they divide, and leave the ear to swell and ripen.
1168. Why are the seeds of plants usually formed within the corollas of flowers?
Because the petals of the flowers, surrounding the seeds, afford them protection until they are ripened, when the flower dies, and the petals fall to the ground.
1169. Why does the flower of the poppy turn down during the early formation of seed?
Because the heat would probably be too great for the seed in its early stage. The plant is therefore provided with a curious curve in its stalk, which turns the flower downward. But when the seeds are prepared for ripening, the stalk erects itself, and the seeds are then presented to the ripening influences of the sun.
1170. Why have plants of the pea tribe, a folding blossom called the "boat," or "keel?"
Because, within that blossom the pea is formed, and the shape of the blossom is exactly suited to that of the pea which is formed therein. The blossom is itself protected by external petals; and when the wind blows, and threatens to destroy the parts upon which the seeds depend, the plants turn their backs to the wind, and shelter the seed.
"The fruit of the righteous is a tree of life; and he that winneth souls is wise."—Proverbs xi.
1171. Why are the leaf buds enclosed in scales which fall off as the leaf opens?
Because the scales serve as a shelter to the tender structure of the young leaf. The scales are rudimentary leaves, formed at the end of the previous season, and which, being undeveloped then, serve to guard the young leaves of the future year.
In trees, especially those which are natives of colder climates, this point is taken up earlier. Many of these trees (observe in particular the ash and the horse-chestnut) produce the embryos of the leaves and flowers in one year, and bring them to perfection the following. There is a winter therefore to be gotten over. Now what we are to remark is, how nature has prepared for the trials and severities of that season. These tender embryos are, in the first place wrapped up with a compactness, which no art can imitate; in which state they compose what we call the bud. This is not all. The bud itself is enclosed in scales; which scales are formed from the remains of past leaves, and the rudiments of future ones. Neither is this the whole. In the coldest climates, a third preservative is added, by the bud having a coat of gum or resin, which, being congealed, resists the strongest frosts. On the approach of warm weather this gum is softened, and ceases to be an hindrance to the expansion of the leaves and flowers. All this care is part of that system of provisions which has for its object and consummation, the production and perfecting of the seeds.—Paley.
1172. Why are the seeds of many plants enclosed in a rich juice, or pulp?
Because the matter by which the seed is surrounded, as well as being intended for the nourishment and care of the seed, is designed for the use of man and of animals, by whom the seed is set free to take its place in the earth.
By virtue of this process, so necessary, but so diversified, we have the seed, at length, in stone-fruits and nuts, incased in a strong shell, the shell itself enclosed in a pulp or husk, by which the seed within is, or hath been, fed; or, more generally (as in grapes, oranges, and the numerous kinds of berries), plunged overhead in a glutinous syrup, contained within a skin or bladder; at other times (as in apples and pears) embedded in the heart of a firm fleshy substance; or (as in strawberries) pricked into the surface of a soft pulp.
These and many more varieties exist in what we call fruits. In pulse, and grain, and grasses; seeds (as in the pea tribe) regularly disposed in parchment pods, which, though soft and membranous, completely exclude the wet even in the heaviest rains; the pod also, not seldom, (as in the bean), lined with a fine down; at other times (as in the senna) distended like a blown bladder; or we have the seed enveloped in wool (as in the cotton-plant), lodged (as in pines) between the hard and compact scales of a cone, or barricadoed (as in the artichoke and thistle) with spikes and prickles; in mushrooms, placed under a pent-house; in ferns, within slits in the back part of the leaf; or (which is the most general organisation of all) we find them covered by strong, close tunicles, and attached to the stem according to an order appropriated to each plant, as is seen in the several kinds of grains and of grasses.
"And I will send grass in thy fields for thy cattle, that thou mayest eat, and be full."—Deuteronomy xi.
In which enumeration, what we have first to notice is, unity of purpose under variety of expedients. Nothing can be more single than the design; more diversified than the means. Pellicles, shells, pulps, pods, husks, skin, scales armed with thorns, are all employed in prosecuting the same intention. Secondly; we may observe, that in all these cases, the purpose is fulfilled within a just and limited degree. We can perceive, that if the seeds of plants were more strongly guarded than they are, their greater security would interfere with other uses. Many species of animals would suffer, and many perish, if they could not obtain access to them. The plant would overrun the soil; or the seed be wasted for want of room to sow itself. It is, sometimes, as necessary to destroy particular species of plants, as it is, at other times, to encourage their growth. Here, as in many cases, a balance is to be maintained between opposite uses. The provisions for the presentation of seeds appear to be directed, chiefly against the inconstancy of the elements, or the sweeping destruction of inclement seasons. The depredation of animals, and the injuries of accidental violence, are allowed for in the abundance of the increase. The result is, that out of the many thousand different plants which cover the earth, not a single species, perhaps, has been lost since the creation.
When nature has perfected her seeds, her next care is to disperse them. The seed cannot answer its purpose, while it remains confined in the capsule. After the seeds therefore are ripened, the pericarpium opens to let them out, and the opening is not like an accidental bursting, but for the most part, is according to a certain rule in each plant. What I have always thought very extraordinary; nuts and shells, which we can hardly crack with our teeth, divide and make way for the little tender sprout which proceeds from the kernel. Handling the nut, I could hardly conceive how the plantule was ever to get out of it. There are cases, it is said, in which the seed-vessel, by an elastic jerk, at the moment of its explosion, casts the seeds to a distance. We all, however, know, that many seeds (those of most composite flowers, as of the thistle, dandelion, &c.) are endowed with what are not improperly called wings; that is, downy appendages, by which they are enabled to float in the air, and are carried oftentimes by the wind to great distances from the plant which produces them. It is the swelling also of this downy tuft within the seed-vessel that seems to overcome the resistance of its coats, and to open a passage for the seed to escape.
But the constitution of seeds is still more admirable than either their preservation or their dispersion. In the body of the seed of every species of plant, or nearly of every one, provision is made for two grand purposes: first, for the safety of the germ; secondly, for the temporary support of the future plant. The sprout, as folded up in the seed, is delicate and brittle beyond any other substance. It cannot be touched without being broken.
Yet in beans, peas, grass-seeds, grain, fruits, it is so fenced on all sides, so shut up and protected, that whilst the seed itself is rudely handled, tossed into sacks, shovelled into heaps, the sacred particle, the miniature plant remains unhurt. It is wonderful, also, how long many kinds of seeds, by the help of their integuments, and perhaps of their oils, stand out against decay. A grain of mustard-seed has been known to lie in the earth for a hundred years; and as soon as it had acquired a favourable situation, to shoot as vigorously as if just gathered from the plant. Then, as to the second point, the temporary support of the future plant, the matter stands thus. In grain, and pulse, and kernels, and pipins, the germ composes a very small part of the seed. The rest consists of a nutritious substance, from which the sprout draws its aliment for some considerable time after it is put forth; viz., until the fibres, shot out from the other end of the seed, are able to imbibe juices from the earth, in a sufficient quantity for its demand. It is owing to this constitution that we see seeds sprout, and the sprouts make a considerable progress, without any earth at all.
"Say not ye, There are four months, and then cometh harvest? behold, I say unto you, Lift up your eyes, and look on the fields; for they are white already to harvest."—John iv.
From the conformation of fruits alone, one might be led, even without experience, to suppose, that part of this provision was destined for the utilities of animals. As limited to the plant, the provision itself seems to go beyond its object. The flesh of an apple, the pulp of an orange, the meat of a plum, the fatness of the olive, appear to be more than sufficient for the nourishing of the seed or kernel. The event shows, that this redundancy, if it be one, ministers to the support and gratification of animal natures; and when we observe a provision to be more than sufficient for one purpose, yet wanted for another purpose, it is not unfair to conclude that both purposes were contemplated together.—Paley.
1173. Why have climbing plants tough curly tendrils?
Because, having no woody stalks of their own to support them, they require to take hold of surrounding objects, and raise themselves from the ground by climbing. Their spiral tendrils are, therefore, so many hands, assisting them to rise from the earth.
1174. Why does the pea put forth tendrils, and the bean not?
Because the bean has in its stalk sufficient woody fibre to support itself, but the pea has not. We do not know a single tree or shrub having a firm strong stem sufficient for its support which is also supplied with tendrils.
1175. Why do the ears of wheat stand up by day, and turn down by night?
Because, when the ear is becoming ripe, the cold dew falling into the ear, might induce blight; the ears therefore turn down to the earth, and receive warmth by radiation.
1176. Why have grasses, corn, canes, &c., joints, or knots in their stalks?
Because a long hollow stem would be liable to bend and break. But the joints are so many points where the fibres are bound together, and the structure greatly strengthened.
"Then shall the earth yield her increase; and God, even our own God, shall bless us."—Psalm xlvii.
1177. Why have the berries of the mistletoe a thick viscid juice?
Because the mistletoe is a parasitical plant, growing upon the bark of other trees. It will not grow in the ground; its seeds are therefore filled with an exceedingly sticky substance, which serves to attach them to the bark of trees, to which the berries attach themselves at once, by throwing out tough fibres; and the next year the plant grows.
Fig. 75.—THE MISTLETOE.
1178. How are the seeds of the mistletoe transferred from its own stem to the bark of trees?
Various birds, and particularly the missel thrush, feed upon the berries. As the bird moves in pursuit of its food, the viscid berries attach themselves to its feathers, and in this way the thrush is the instrument which conveys the seed to the spot to which it adheres, and from which the tree ultimately grows.
1179. What is the circulation of the sap in plants?
The circulation of the sap is the movement of the nutritive juices by which the plant is sustained. There is a slow uninterrupted movement of the sap from the root through the stems to the leaves, and downwards from the leaves through the bark to the root.
"For the sun is no sooner arisen with a burning heat, but it withereth the grass, and the flower thereof falleth, and the grace of the fashion of it perisheth: so also shall the rich man fade away in his ways."—James i.
1180. Why does the sap of plants thus ascend and descend?
Because it conveys upward from the ground some of the matter by which the plant is to be nourished, and which must undergo digestion in the leaves; and it brings downward from the leaves the matters absorbed, for the nourishment of the plant, and discharges through the root the substances which the plant cannot use.
The movement of the sap is most active in the spring; but in the depths of the winter it almost ceases.
There are other motions of the sap in plants, which are called special, in distinction from the ascending and descending of the sap, which is called general, or common to all plants. The special movements of the sap are peculiar to certain plants, in some of which a fluid, full of little green cells, is found to have a rotatory motion; in other plants, a milky fluid is found to move through particular tissues of the vegetable structure.
1181. Why are the leaves of plants green?
Because they secrete a carbonaceous matter, named chlorophyll, from which they derive their green colour.
1182. Why are the hearts of cabbages, lettuces, &c., of a pale yellow colour?
Because the action of light is necessary to the formation of chlorophyll; and as the leaves are folded upon each other, they exclude the light, and the green matter is not formed.
1183. Why do leaves turn brown in the autumn?
Because, when their power of decomposing the air declines, the oxygen absorbed in the carbonic acid gas, lodges in the leaf, imparting to it a red or brown colour.
1184. Why do succulent fruits, such as gooseberries, plums, &c., taste acid?
Because, in the formation of juices, a considerable amount of oxygen is absorbed, and the oxygen imparts acidity to the taste.
"The earth is full of the goodness of the Lord."—Psalm xxxiii.
1185. Why do ripe fruits taste sweet, and unripe fruits taste sour?
Because the juices of the ripe fruit contain a large proportion of sugar, which in the unripe fruit has not been formed.
1186. Why do some leaves turn yellow?
Because they retain an excess of nitrogen. Leaves undergoing decay turn either yellow, red, crimson, or violet. Yellow is due to the excess of nitrogen; red and crimson to various proportions of oxygen; violet to a mixture of carbon; and green to chlorophyll.
1187. Why do leaves fall off in the autumn?
Because they have supplied for a season the natural wants of the tree. Every part has received nutrition through the spring and summer months; and the wants of the tree being supplied, the chief use of the leaf ceases, and it falls to the ground to decay, and enrich the soil.
1188. Why do plants suffer from the smoke of cities?
Because the smoke injures the porous structure of the leaves, and interferes with their free respiration.
CHAPTER LXI.
1189. Why are vegetable productions so widely diffused?
Because they everywhere form the food of the animal creation. Without them, neither man nor beast could exist. Even the flesh-eating animals are sustained by them, since they live by preying upon the bodies of vegetable-eaters.
They also enrich and beautify the earth. They present the most charming diversities of proportions and features. From the cowslip, the primrose, and the blue-bell of our childish days, to the broad oak under which we recline, while children gambol round us, they are all beautiful or sublime, and eminently useful in countless ways to man.
They spread a carpet over the surface of the earth; they cling to old ruins, and cover hard rocks, as though they would hide decay, and give warmth to the coldness of stone. In tropical climates they supply rich fruits full of cool and refreshing juices, and they spread out upon the crests of tall trees those broad leaves which shelter the native from the scorching heat of the sun.
They supply our dwellings with furniture of every kind, from the plain deal table, to the handsome cabinet of satin or rose-wood; they afford rich perfumes to the toilette, and luscious fruits and wines to the desert; they charm the eye of the child in the daisied field; they adorn the brow of the bride; they are laid in the coffin with the dead; and, as the cypress or the willow bend over our graves, they become the emblems of our grief.
"The glory of the Lord shall endure for ever: the Lord shall rejoice in his works."—Psalm civ.
Mahogany is the wood of trees brought chiefly from South America and Spain. The finest kind is imported from St. Domingo, and an inferior kind from Honduras.
We all know the beauty of mahogany wood. But we do not all know that mahogany was first employed in the repair of some of Sir Walter Raleigh's ships at Trinidad in 1597. The discovery of the beauty of its grain for furniture and cabinet work was accidental. Dr. Gibbons, a physician of eminence, was building a house in King-street, Covent-garden; his brother, captain of a West Indiaman, had brought over some planks of mahogany as ballast, and he thought that the wood might be used up in his brother's building, but the carpenters found the wood too hard for their tools, and objected to use it. Mrs. Gibbons shortly afterwards wanted a small box made, so the doctor called upon his cabinet-maker, and ordered him to make a box out of some wood that lay in his garden. The cabinet-maker also complained that the wood was too hard. But the doctor insisted upon its being used, as he wished to preserve it as a memento of his brother. When the box was completed, its fine colour and polish attracted much attention; and he, therefore, ordered a bureau to be made of it. This was done, and it presented so fine an appearance that the cabinet-maker invited numerous persons to see it, before it was sent home. Among the visitors was her Grace the Duchess of Buckingham, who immediately begged some of the wood from Mr. Gibbons, and employed the cabinet-maker to make her a bureau also. Mahogany from this time became a fashionable wood, and the cabinet-maker, who at first objected to use it, made a great success by its introduction.
Rosewood is the wood of a tree which grows in Brazil. It is, generally speaking, too dark for large articles of furniture, but is admirably adapted for smaller ones. It is expensive, and the hardness of the wood renders the cost of making articles of it very high.
"I am come up to the height of the mountains, to the sides of Lebanon, and will cut down the tall cedars thereof, and the choice fir trees thereof."—II. Kings xxiii.
Respecting the other woods used in the manufacture of furniture, we have nothing special to say, except of the oak—the emblem of our native land. This tree yields a most useful and durable wood, and as it not only defends our country by supplying our "wooden walls," but gives to us the floors of our houses, furnishes our good substantial tables, and comfortable arm-chairs, it will be well for us to know a few facts about this celebrated tree. It is said that there are no less than one hundred and fifty species of the oak. The importance of the growth of oaks may be gathered from the fact, that the building of a 70-gun ship would take forty acres of timber. The building of a 70-gun ship is estimated to cost about £70,000. Oak trees attain to the age of 1,000 years. The oak enlarges its circumference from 10½ inches to 12 inches in a year. The interior of a great oak at Allonville, in Normandy, has been converted into a place of worship. An oak at Kiddington, served as a village prison. A large oak at Salcey, was used as a cattle fold; and others have served as tanks, tombs, prisons, and dwelling-houses.
The Mammoth tree, which is exhibiting at the Crystal Palace, is one of the great wonders of the vegetable creation. It is the grand monarch of the Californian forest, inhabiting a solitary district on the elevated slopes of the Sierra Nevada, at 5,000 feet above the sea-level. From 80 to 90 trees exist, all within the circuit of a mile, and these varying from 250 to 320 feet in height, and from 10 to 20 feet in diameter. The bark is from 12 to 15 inches in thickness; the branchlets are somewhat pendent, and resemble those of cypress or juniper, and it has the cones of a pine. Of a tree felled in 1853, 21 feet of the bark from the lower part of the trunk were put in the natural form as a room, which would contain a piano, with seats for forty persons; and on one occasion 150 children were admitted. The tree is reputed to have been above 3,000 years old; that is to say, it must have been a little plant when Samson was slaying the Philistines. The portion of the tree exhibiting at the palace is 103 feet in height, and 32 feet in diameter at the base.
Tea is the leaf of a shrub (Thea Chinensis). The plant usually grows to the height of from three to six feet, and resembles in appearance the well-known myrtle. It bears a blossom not unlike that of the common dog-rose. The climate most congenial to it is that between the 25th and 33rd degrees of latitude. The growth of good tea prevails chiefly in China, and is confined to a few provinces. The green and black teas are mere varieties, depending upon the culture, time of gathering, mode of drying, &c. Coffee was used in this country before tea. in 1664, it is recorded, the East India Company bought 2lb. 2oz. of coffee as a present for the king. In the year 1832, there were 101,687 licensed tea dealers in the United Kingdom. Green tea was first used in 1715. A dispute with America about the duty upon tea led to the American war, out of which arose American independence. The consumption of tea throughout the whole world is estimated at above 52,000,000 lbs., of which the consumption of Great Britain alone amounts to 30,000,000. (See [1225]).
"Every man should eat and drink, and enjoy the good of all his labour, it is the gift of God."—Ecclesiastes iii.
Coffee is the berry of the coffee plant, which was a native of that part of Arabia called Yemen, but it is now extensively cultivated in India, Java, the West Indies, Brazil, &c. (See [1224]).
The first coffee-house in London was opened in 1652, under the following circumstances. A Turkey merchant named Edwards, having brought along with him from the Levant, some bags of coffee, and a Greek servant who was skilful in making it, his house was thronged with visitors to see and taste this new beverage. Being desirous to gratify his friends without putting himself to inconvenience, he allowed his servant to open a coffee-house, and to sell coffee publicly.
Here we have another illustration of the great results springing from trifling causes. Coffee soon became so extensively used that taxes were imposed upon it. In 1660 a duty of 4d. a gallon was imposed upon all coffee made and sold. Before 1732 the duty upon coffee was 2s. a pound; it was afterwards reduced to 1s. 6d., at which it yielded to the revenue, for many years, £10,000 per annum. The duty has been gradually reduced, and the consumption has gone on increasing, until at last above 25,000,000 of pounds are consumed annually! Fancy this great result springing from a "friendly coffee party" that assembled in the year 1652.
It is a cake prepared from the cocoa-nut. The nut is first roasted like coffee, then it is reduced to powder and mixed with water, the paste is then put into moulds and hardened. The properties are very healthful, but its consumption is very insignificant, as compared with tea or coffee. The cocoa tree grows chiefly in the West Indies and South America.
Cocoa is also a preparation from the seeds or beans of the cocoa tree. But the best form of cocoa for family use is to obtain the beans pure, as they are now commonly sold ready for use, and to break them and then grind them in a large coffee mill.
Chicory is the root of the common endive, dried and roasted as coffee, for which it is used as a substitute. Some persons prefer the flavour of chicory admixed with coffee. But very opposite opinions prevail respecting the qualities of chicory. We believe it to be perfectly healthful, and attribute the prejudice that prevails against it, to its having been used, from its cheapness, to adulterate coffee.
"He that tilleth the land shall have plenty of bread: but he that followeth after vain persons shall have poverty enough."—Proverbs xxviii.
Sugar is a sweet granulated substance, which may be derived from many vegetable substances, but the chief source of which is the sugar cane. The other chief sources that supply it are the maple, beet-root, birch, parsnip, &c. It is extensively used all over the world. Sugar is supposed to have been known to the ancient Jews. It was found in the East Indies by Newcheus, Admiral of Alexander, 325 B.C. It was brought into Europe from Asia.
The art of sugar refining was first practised in England, in 1659, and sugar was first taxed by name by James II., 1685. Sugar is derived from the West Indies, Brazil, Surinam, Java, Mauritius, Bengal, Siam, the Isle de Bourbon, &c. &c. Before the introduction of sugar to this country, honey was the chief substance employed in making sweet dishes; and long after the introduction of sugar it was used only in the houses of the rich. The consumption in England in 1700 reached only 10,000 tons; in 1834 it had reached 180,000 tons. The English took possession of the West Indies in 1672, and in 1646 began to export sugar. In 1676 it is recorded that 400 vessels, averaging 150 tons, were employed in the sugar trade of Barbadoes. Jamaica was discovered by Columbus, and was occupied by the Spaniards, from whom it was taken by Cromwell, in 1656, and has since continued in our own possession. When it was conquered there were only three sugar plantations upon it. But they rapidly increased. Until the abolition of slavery in the West Indies, the production of sugar was almost exclusively limited to slave labour. (See [1226]).
Wheat, rye, barley, oats, millet, and maize, all belong to the natural order of grain-bearing plants. They all grow in a similar manner, and all yield starch, gluten, and a certain amount of phosphates. They are commonly spoken of as farinaceous foods.
"I clothed thee also with broidered work, and shod thee with badgers' skin, and I girded thee about with fine linen, and I covered thee with silk."—Ezekiel xvi.
From the Sacred writings we learn that unleavened bread was common in the days of Abraham. In the earlier periods of our own history, people had no other method of making bread than by roasting corn, and beating it in mortars, then wetting it into a kind of coarse cake. In 1596, rye bread and oatmeal formed a considerable part of the diet of servants, even in great families. In the time of Charles the First, barley bread was the chief food of the people. In many parts of England it was more the custom to make bread at home than at present. In 1804, there was not a single public baker in Manchester. In France, when the use of yeast was first introduced, it was deemed by the faculty of medicine to be so injurious to health that its use was prohibited under the severest penalties. Herault says that, during the siege of Paris by Henry the Fourth, a famine raged, and bread sold at a crown a pound. When this was consumed, the dried bones from the charnel house of the Holy Innocents were exhumed, and a kind of bread made therefrom. Bread-street, in London, was once a bread market. From the year 1266, it had been customary to regulate by law the price of bread in proportion to the price of wheat or flour at the time. This was called the assize of bread; but, in 1815, it was abolished. In the year 272 there was a famine in Britain so severe that people ate the bark of trees; forty thousand persons perished by famine in England in 310! In the year 450 there was a famine in Italy so dreadful that people ate their own children. A famine, commencing in England, Wales, and Scotland, in 954, lasted four years. A famine in England and France, in 1193, led to a pestilential fever, which lasted until 1195. In 1315 there was again a dreadful famine in England, during which people devoured the flesh of horses, dogs, cats, and vermin! In the year 1775, 16,000 people died of famine in the Cape de Verds. These are only a few of the remarkable famines that have occurred in the course of history. Let us thank God that we live in times of abundance, when improved cultivation, the pursuit of industry, and the settlement of the laws, render such a calamity as a famine almost an impossibility.
Cotton is a species of vegetable wool, produced by the cotton shrub, called, botanically, Gossypium herbaceum, of which there are numerous varieties. It grows naturally in Asia, Africa, and America, and is cultivated largely for purposes of commerce.
The precise time when the cotton manufacture was introduced into England is unknown; but probably it was not before the 17th century. Since then, what wonderful advances have been made! The cotton trade and manufacture have become a vast source of British industry, and of commerce between nations. It was some years ago calculated that the cotton manufacture yielded to Great Britain one thousand millions sterling. The names of Hargreaves, Arkwright, Crompton, Cartwright, and others, have become immortalised by their inventions for the improvement of the manufacture of cotton fabrics. Little more than half a century has passed since the British cotton manufactory was in its infancy—now it engages many millions of capital—keeps millions of work people employed; freights thousands of ships that are ever crossing and re-crossing the seas; and binds nations together in ties of mutual interest. The present yearly value of cotton manufactures in Great Britain is estimated at £34,000,000. About £6,044,000 of the above sum is distributed yearly among working people as wages.
Silk, though not directly a vegetable product, is, nevertheless, indirectly derived from the vegetable creation, since it is a thread spun by the silk-worm from matter which the worm derives from the mulberry leaf.
"And there was a man in Maon, whose possessions were in Carmel; and the man was very great, and he had three thousand sheep, and a thousand goats: and he was shearing his sheep in Carmel."—I Samuel xxv.
Silk is supplied by various parts of the world, including China, the East Indies, Turkey, &c., where the silk-worm has been found to thrive. The attempts that have been hitherto made to cultivate it in this country have proved unsuccessful. At Rome, in the time of Tiberius, a law passed the senate which, as well as prohibiting the wearing of massive gold jewels, also forbade the men to debase themselves by wearing silk. There was a time when silk was of the same value as gold—weight for weight—and it was thought to grow upon trees. It is recorded that silk mantles were worn by some noble ladies at a ball at Kenilworth Castle, 1286. It was first manufactured in England in 1604. In the reign of Elizabeth, the manufacture of silk in England made rapid strides. In 1666, there were 40,000 persons engaged in the silk trade. The silk throwsters of the metropolis were enrolled in a fellowship in 1562, and were incorporated in 1629. In 1685, a considerable impetus was given to the English silk manufactures. Louis the Fourteenth of France revoked the edict of Nantes. The edict of Nantes was promulgated by Henry the Fourth of France in 1598. It gave to the Protestants of France the free exercise of their religion. Louis the Fourteenth revoked this edict in 1685, and thereby drove the Protestants as refugees to England, Holland, and parts of Germany, where they established various manufactures. Many of these French refugees settled in Spitalfields, and there founded extensive manufactories, which soon rivalled those of their own country; and thus the intolerance of the king was justly punished. What important facts we see connected with the simple thread of the silk-worm!
Wool is a kind of soft hair or coarse down, produced by various animals, but chiefly by sheep.
This is another of the useful productions of nature, for which we are indirectly indebted to the vegetable kingdom; for were it not for the rich pastures forming the green carpet of the earth, it would be impossible for man to keep large flocks of sheep for the production of wool. Wool, like the hair of most animals, completes its growth in a year, and then exhibits a tendency to fall off. For the production of wool in England and Wales it has been estimated that there are no less than 27,000,000 sheep and lambs; and, in Great Britain and Ireland, the total number is estimated at 82,000,000. Wool was not manufactured in any quantity in England until 1331, when the weaving of it was introduced by John Kempe and other artizans from Flanders. The exportation or non-exportation of wool has from time to time formed a vexed subject for legislators. Woollen clothes were made an article of commerce in the reign of Julius Cæsar. They were made in England prior to 1200. Blankets were first made in England in 1340. The art of dyeing wools was first introduced into England in 1608. The annual value of the raw material in wool is set down at £6,000,000; the wages of workmen engaged in the wool trade, £9,600,000. The number of people employed is said to be 500,000.
Starch is one of the most useful products of the vegetable kingdom. As a rule, a vegetable, if nutritious at all, is so according to the amount of starch which it contains. It is most abundantly found in the seeds of plants, and especially in the wheat tribe.
It is also met with in the cellular tissues of plants, and especially in such underground stems as the potatoe, carrot, turnip, &c., and the stems of the sago-palm fig, &c. It is also found in the bark of some trees.
"Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning."—James i.
1203. Why is the horse chestnut, though containing a great quantity of starch, unfit for food?
Because (like many other vegetable productions) it contains with the starch an acrid juice, which renders it unhealthy; and although the juice can be separated from the starch, the process is too expensive to be made generally available.
The starch which is used for domestic purposes is an artificial preparation, and does not properly represent the starch of nutrition. A better idea of it is afforded by the meal of a flowery potatoe. The starch used by laundresses is frequently prepared from diseased potatoes. This does not impair the quality of the starch, for the purposes of the laundress, and the reason why potatoes that are diseased are thus applied is, that it is one method of saving some part of their value. The finest kinds of starch are prepared from rice. It is prepared by breaking the pulp, and disengaging the starch from the cells; and it is then put through other processes to remove the fragments of the broken cells. But in the flowery meal of the potatoe, the starch cell may be seen entire.
CHAPTER LXII.
1204. What are vegetable oils and fats?
Vegetable oils and fats constitute, next to starch and sugar, the most important secretion of the vegetable creation. There are very few plants from which some amount of oil cannot be obtained; and those which are famed for yielding it owe their celebrity rather to the abundance that they yield, and the peculiar qualities of their oil, than to the secretion of oil being rare—for probably there is no plant without it.
Oil is most commonly found in seeds, as rape-seed, linseed, &c., but it is found also in leaves, as in the rose, sweet-briar, peppermint, &c., where its presence may be recognised by the distinguishing perfume; and it is also found in the wood of a few trees, such as the sassafras and the sandal-wood; the bark frequently yields an oily secretion.
"Ointment and perfume rejoice the heart; so doth the sweetness of a man's friend by hearty counsel."—Proverbs xxvii.
The London and North Western Railway Company alone use about 50,000 gallons of oil yearly.
1205. Why are fat and oil found most abundantly in the bodies of animals in cold climates?
Because they contribute to keep the bodies of animals warm, not only by their non-conducting property keeping in the heat of the animals, but by supplying carbon abundantly to combine with oxygen during respiration, and thereby developing animal heat.
1206. Why are oil and fat-forming trees found most abundantly in hot climates?
Because, in hot countries, the formation of large quantities of fat in animal bodies would oppress living creatures with heat; fats and oils are, therefore, produced in those countries chiefly by vegetables, and are used externally by the Asiatics and Africans as an external unction for cooling the skin, and as perfumes which give inspiriting properties to the air, rendered oppressive by excess of heat.
1207. Why are succulent fruits most abundant in tropical climates?
Because they are rendered necessary in those climates by the excessive heat, and are found to have a most beneficial effect in cooling, purifying the blood of the inhabitants of tropical countries; while the grandeur of their foliage, and the richness of their flowers, are in perfect keeping with the intensity of light and heat, and serve, by throwing dense shades over the earth, to cool its surface, and to offer to living creatures a pleasant retreat from the rays of the burning sun.
The following sketch of Botanical Geography should be read attentively after the reader has gone through the whole of the Chapters of "Reasons." The technical terms employed in the course of the article are nearly all explained at 1212, and should be committed to memory at the commencement of the perusal. Mimosa means a sensitive plant; concentric zones, circular lines spreading from a centre; arborescent, resembling trees; Gramineæ, grass-like. The botanical names represent individual plants.
"Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful:"
1208. When treating of the geographical distribution of vegetables, we have to mark the general arrangements indicated, and the agencies that have evidently operated in promoting the diffusion of floral tribes. Vegetation occurs over the whole globe, therefore, under the most opposite conditions. Plants flourish in the bosom of the ocean as well as on land, under the extremes of cold and heat in polar and equatorial regions, on the hardest rocks and the soft alluvium of the plains, amidst the perpetual snow of lofty mountains, and in springs at the temperature of boiling water, in situations never penetrated by the solar rays, as the dark vaults of caverns, and the walls of mines, as well as freely exposed to the influences of light and air. But these diverse circumstances have different species and genera. There is only one state which seems fatal to the existence of vegetable life—the entire absence of humidity.
1209. By species we understand so many individuals as intimately resemble each other in appearance and properties, and agree in all their permanent characters, which are founded in the immutable laws of creation. An established species may frequently exhibit new varieties, depending upon local and accidental causes, but these are imperfectly, or for a limited time, if at all, perpetuated.
1210. A genus comprises one or more species similar to each other, but essentially differing in formation, nature, and in many adventitious qualities from other plants. A tribe, family, group, or order, comprises several genera.
1211. The known number of species in the vegetable kingdom has been gradually enlarged by the progress of maritime and inland discovery; but owing to great districts of the globe not having yet been explored by the botanist, the interior of Africa, and Australia, with sections of America, Asia, and Oceanica, it is impossible to state the exact amount. The successive augmentation of the catalogue appears from the numbers below:
| Species. | |
|---|---|
| Theophrastus | 500 |
| Pliny | 1,000 |
| Greek, Roman, and Arabian botanists | 1,400 |
| Bauhin | 6,000 |
| Linnæus | 8,800 |
| Persoon | 27,000 |
| Humboldt and Brown | 38,000 |
| De Candolle | 56,000 |
| Lindley | 86,000 |
| Hinds | 89,000 |
1212. Vegetable forms are divided into three great classes which differ materially in their structure:—1. Cryptogamous plants—those which have no flowers, properly so called, mosses, lichens, fungi, and ferns: as distinguished from those which are phænogamous, or flower-bearing, to which the two following classes belong. 2. Endogenous plants, which have stems increasing from within, also called Monocotyledons, from having only one seed-lobe, as the numerous grasses, lilies, and the palm family. 3. Exogenous plants, which have stems growing by additions from without, also called Dicoteledons, from the seed consisting of two lobes, the most perfect, beautiful, and numerous class, embracing the forest trees, and most flowering shrubs and herbs.
1213. The exogens furnish examples of gigantic size, and great longevity. In South America on the banks of the Atabapo, Humboldt measured a Bombax caiba more than 120 feet high, and 15 in diameter; and near Cumana, he found the Zamang del Guayra, a species of mimosa, the pendant branches of the hemispherical head having a circumference of upwards of 600 feet. The Adansonia, or baobab of Senegal, though attaining no great height, rarely more than fifty feet, has a trunk with a diameter sometimes amounting to 34 feet; while the Pinus Lambertiana, growing singly on the plains west of the Rocky Mountains, has been found 250 feet high, 60 feet in circumference at the base, 4½ feet in girth at the height of 190 feet, yielding cones 11 inches round, and 16 long. The Ficus Indicus, or banian tree, sending out shoots from its horizontal branches, which reaching the ground take root, and form new stems till a single tree multiplies almost to a forest, has been observed covering an area of 1700 square yards.
"He shall be like a tree planted by the rivers of water, that bringeth forth his fruit in season: his leaf also shall not wither; and whatsoever he doeth shall prosper."—Psalm i.
1214. From the number of concentric zones observed in a transverse section of the stems De Caudolle advances proof of the following ages:
| Elm | 335 | years. | |
| Cypress | about 350 | " | |
| Cheirostemon | 400 | " | |
| Ivy | 450 | " | |
| Larch | 576 | " | |
| Orange | 630 | " | |
| Olive | 700 | " | |
| Oriental Plane | 720 | " | and upwards. |
| Cedar of Lebanon | 800 | " | |
| Oak | 810, 1080, 1500 | " | |
| Lime | 1076, 1147 | " | |
| Yew | 1214, 1458, 2588, 2880 | " | |
| Taxodium | 4000 to 6000 | " | |
| Baobab | 5150 | " |
1215. Admitting, with Professor Henslow, that De Candolle overrated the ages of these trees one-third, they are examples of extraordinary longevity. Yew trees upwards of 700 years old remain at Fountains Abbey, Yorkshire, as there is historic evidence of their existence in the year 1133. But a yew in the churchyard of Darley-in-the-Dale, Derbyshire, is considered by Mr. Bowman as 2000 years old.
1216. The cryptogamous plants afford the most numerous examples of wide diffusion. A lichen indigenous in Cornwall, sticta aurata, is also a native of the West India Islands, Brazil, St Helena, and the Cape of Good Hope; while 38 lichens and 28 mosses are common to Great Britain and Australia, though the general vegetation of the two districts is remarkably discordant. Some species of endogenous plants are also widely distributed, the Phleum alpinum of Switzerland occurring without the slightest difference at the Strait of Magellan, and the quaking grasses of Europe in the interior of Southern Africa. But only in very few instances are the same species of exogenous plants met with in regions far apart from each other; and generally speaking, in passing from one country to another, we encounter a new flora; for if the same genera occur, the species are not identical, while in districts widely separated the genera are different.
1217. The cryptogamic plants, mosses, lichens, ferns, and fungi, are to the whole mass of phænogamic vegetation in the following proportions in different districts: Equatorial latitudes, 0 deg. to 10 deg.; on the plains, 1-25th, on the mountains, 1-5th; mean latitudes, 45 deg. to 52 deg. ½; high latitudes, 67 deg. 70 deg., proportion about equal. Thus the proportion of the flowerless vegetation to the flowering increases from the equator to the poles. But the family of ferns, filices, viewed singly, forms an exception to this law, decreasing as we depart from equinoctial countries, being 1-20th in equatorial and 1-70th in mean latitudes, and not found at all in the high latitudes of the new world.
"To give unto them beauty for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness; that they might be called Trees of righteousness, The planting of the Lord, that he might be glorified."—Isaiah lxi.
1218. In equinoctial and tropical countries, where a sufficient supply of moisture combines with the influence of light and heat, vegetation appears in all its magnitude and glory. Its lower orders, mosses, fungi, and confervæ, are very rare. The ferns are aborescent. Reeds ascend to the height of a hundred feet, and rigid grasses rise to forty. The forests are composed of majestic leafy evergreen trees bearing brilliant blossoms, their colours finely contrasting, scarcely any two standing together being of the same species. Enormous creepers climb their trunks; parasitical orchidæ hang in festoons from branch to branch, and augment the floral decoration with scarlet, purple, blue, rose, and golden dyes. Of plants used by man for food, or as luxuries, or for medicinal purposes, occurring in this region, rice, bananas, dates, cocoa, cacao, bread-fruit, coffee, tea, sugar, vanilla, Peruvian bark, pepper, cinnamon, cloves, and nutmegs, are either characteristic of it as principally cultivated within its limits, or entirely confined to them.
1219. Rice (Oryza-sativa), the chief food of, perhaps, a third of the human race, is cultivated beyond the tropics, but principally within them, only where there is a plentiful supply of water. It has never been found wild; its native country is unknown; but probably southern Asia.
1220. Bananas, or plantains (Musa sapientum et paradisiaca), are cultivated in intertropical Asia, Africa, and America. The latter species occur in Syria. The banana is not known in an uncultivated state. Its produce is enormous, estimated to be on the same space of ground to that of wheat, as 133 to 1, and to that of potatoes as 44 to 1.
1221. Dates (Phœnix dactylifera), and cocoa (Cocos nucifera), belonging to the family Palmæ. The palms, remarkable for their elegant forms and importance to man, contribute more than any other trees to impress upon the vegetation of tropical and equinoctial countries its peculiar physiognomy. The date palm is a native of northern Africa, and is so abundant between the Barbary states and the Sahara, that the district has been named Biledul erid, the land of dates. As the desert is approached, the only objects that break the monotony of the landscape are the date palm, and the tent of the Arab. It accompanies the margin of the mighty desert in all its sinuosities from the shores of the Atlantic to the confines of Persia, and is the only vegetable affording subsistence to man that can grow in such an arid situation. The annual produce of an individual is from 150 to 260lbs. weight of fruit. The cocoa palm furnishes annually about a hundred cocoa-nuts. It is spread throughout the torrid zone; but occurs most abundantly in the islands of the Indian archipelago. The family of palms is supposed to contain a thousand species, some of large size, forming extensive forests.
1222. Cacao (Theobrama cacao), from the seeds of which chocolate is prepared, grows wild in central America, and is also extensively cultivated in Mexico, Guatemala, and on the coast of Cumana.
1223. Bread-fruit tree (Artocarpus incisa), a native of the South Sea Islands, and Indian archipelago, grows also in Southern Asia, and has been introduced into the tropical parts of America; but the fruit is not equal to the banana as an article of human food.
"And they returned and prepared spices and ointments; and rested the Sabbath-day, according to the commandment."—Luke xxiv.
1224. Coffee (Coffea Arabica). The bush has probably for its native region the Ethiopian Highlands, from whence it was taken in the fifteenth century to the Highlands of Yemen, the southern part of the Arabian peninsula. It has been introduced, and is now extensively cultivated in British India, Java, Ceylon, the Mauritius, Brazil, and the West Indies, but the quality is inferior, which makes the climate of the Mocha coffee district of importance, as peculiarly favourable to the plant. It grows there on hills described by Niebuhr as being soaked with rain every day from the beginning of June to the end of September, which is carefully collected for the purpose of irrigation during the dry season. Forskhal gives the following temperatures in the district:
| Boit el Fakih | March 16, | 7 A.M. | 76 deg. | 1 P.M. | 95 deg. | 10 P.M. | 81 deg. |
| " | March 18, | " | 77 deg. | " | 95 deg. | " | 81 deg. |
| Hodeida | March 18, | " | 72 deg. | " | 92¾ deg. | " | 78 deg. |
| Bulgosa, a village in the hills | March 20, | " | 69½ deg. | " | 85½ deg. | " | 73 deg. |
1225. Tea (Thea Chinensis). The plant is indigenous in China, Japan, and Upper Assam. In the latter country, it has recently been found in a wild state, and is in process there of extensive cultivation. As the plant is hardy, its culture has very lately been attempted in the South of France, and apparently with complete success. A similar experiment on the burning plains of Algeria completely failed, all the plants being killed by the heat, notwithstanding every precaution. Tea was first introduced into Europe by the Dutch in 1666. The leaves of the coffee-plant have long been used as a substitute for tea, by the lower classes in Java and Sumatra; and recently, Professor Blume, of Leyden, exhibited samples of tea prepared from coffee-leaves, agreeing entirely in appearance, odour, and taste, with the genuine Chinese production.
1226. Sugar-cane (Saccharum officinaram), a species of Gramineæ, occurs to some extent without the tropics, having been cultivated centuries ago in Europe, as at present scantily in the South of Spain. But it properly belongs to the torrid zone, and has for its principal districts, the Southern United States, the West Indies, Venezuela, Brazil, the Mauritius, British India, China, the Sunda and Philippine Islands. The plant was found wild in several parts of America on the discovery of that continent, and occurs in a wild state on many of the islands of the Pacific.
1227. Vanilla (Vanilla aromatica), the fruit of which forms the well-known aromatic, grows wild principally in Mexico.
1228. Peruvian bark (Cinchona officinalis), a forest tree, of which there are several species, furnishing the valuable medicine so called. It is exclusively confined to South America, and grows chiefly on the Andes of Loxa and Venezuela.
1229. Pepper (Piper nigrum) belongs exclusively to the Malabar coast, where it has been found wild, Sumatra, which produces the greatest quantity, Borneo, the Malay peninsula, and Siam. Other species of Piperaceœ occur in tropical America.
1230. Cinnamon (Laurus Cinnamomum), a small tree yielding the aromatic bark, is found native only in the island of Ceylon; but another species occurs in Cochin China.
"I am the true vine, and my Father is the husbandman."—John xv.
1231. Clove (Myrtus caryophyllus), an evergreen small tree, the dried flower-buds of which form the celebrated aromatic, grows naturally in the Moluccas, whence it has been conveyed to other tropical districts. The island of Amboyna, one of that group, is the principal seat of its cultivation. The lowest temperature there is 72 degs.; the mean temperature of the year 82 degs.
1232. Nutmeg (Myrstica moschata) grows naturally in several islands of the eastern archipelago, but is principally cultivated in the Banda Isles.
Tropical families and forms successively vanish with an increase of distance from the equator, and new phases of vegetation mark the transition from hot to temperate climates. Vividly green meadows, abounding with tender herbs, replace the tall rigid grasses which form the impenetrable jungle; and instead of forests composed of towering evergreen trees, woods of the deciduous class appear, which cast their leaves in winter, and hybernate in the colder season, the oak, ash, elm, maple, beech, lime, alder, birch, and sycamore. The cultivation of the vine becomes characteristic, with the perfection of the cereal grasses, and a larger proportion of herbaceous annuals and cryptogamic plants.
1233. The vine (Vitis vinifera) is less impatient of a cold winter than a cool summer. Hence its northern limit, which coincides with lat. 47 deg. 30 min. on the west coast of France, rises in the interior, where, though the winters are colder, the summers are warmer, to lat. 49 degs., cuts the Rhine at Coblentz in lat. 50 deg. 20 min., and ascends to 52 deg. 31 min. in Germany.
1234. Receding further from the equator, magnificent forests of the fir and pine tribe prevail, as in the central parts of Russia, on the southern shores of the Baltic, in Scandinavia, and North America. But some of the cereals are no longer cultivatable, and several timber-trees common to the temperate zone do not reach its northern limits. Gradually all ligneous vegetation disappears entirely as higher latitudes are approached, the woods having first dwindled to mere dwarfs in struggling with the elements, hostile to that state which nature destined them to assume. The limit of the forests is a sinuous line running along the extreme north of the old world; and extending from Hudson's Bay, lat. 60 deg., to the Mackenzie River, lat. 68 deg., and thence to Behring's Strait. The dwarf birch (Betula nana), a mere bush, is the last tree found on drawing near the eternal snow of the pole. At the island of Hammerfest, lat. 70 deg. 40 min., near the North Cape, it rises to about the height of a man, in sheltered hollows between the mountains, its lower branches trailing on the ground, affording a shelter to the ptarmigan. In the polar zone, some low flowering annuals, saxifrages, ranunculi, gentians, chickweeds, and others, flourish during the brief ardent summer; a few perennials also accommodate themselves to the rigorous climate by spreading laterally, never rising higher than four or five inches from the ground; till finally no development of vegetable life is met with, but lichens, and the microscopic forms that colour the snow.
1235. In Europe, wheat ceases with a line connecting Inverness in Scotland, lat. 58 deg., Drontheim in Norway, lat. 64 deg., and Petersburgh in Russia lat. 60 deg. 15 min. Oats reach a somewhat higher latitude. Barley and rye ascend to lat. 70 deg., but require a favourable aspect and season to produce a crop.
1236. The northern limit of the growth of oak, lat. 61 deg., falls short of that of wheat. The oak makes a singular leap at the confines of Europe and Asia, disappearing towards the Ural mountains. This is the case also with the wild-nut and apple. The oak and the wild-nut, however, re-appear suddenly in Eastern Asia, on the banks of the Argoun and the Amour; and the apple occurs again in the Aleutian Isles.
"He hath made the earth by his power, he hath established the world by his wisdom, and hath stretched out the heavens by his discretion."—Jeremiah x.
1237. The following are the northern limits of several trees in Scandinavia:
| Lat. | |||||
|---|---|---|---|---|---|
| Beech, Fagus silvatica | 60 | deg. | 0 | min. | |
| Hard Oak, Quercus robur | 61 | " | 0 | " | |
| Common Elm, Ulmus campestris | 61 | " | 0 | " | |
| Common Lime, Tilia communis | 61 | " | 0 | " | |
| Common Ash, Fraxinus excelsior | 62 | " | 0 | " | |
| Fruit trees | 63 | " | 0 | " | |
| Hazel, Corylus, avellana | 64 | " | 0 | " | |
| Spruce Fir, Abies excelsa | 67 | " | 40 | " | |
| Service Tree, Sorbus aucuparia | 70 | " | 0 | " | |
| Scotch Fir, Pinus silvestris | 70 | " | 0 | " | |
| White Birch, Betula alba | 70 | " | 40 | " | |
| Dwarf Birch, Betula nana | 71 | " | 0 | " | |
1238. Thus distinct vegetable regions are observed on passing from south to north through different climatic zones, defined as to their limits by the isothermal curves, and not by the parallels of latitude. Similar changes of vegetation mark a perpendicular transit through varying climates. A succession of plants appear on the tropical mountains which rise above the snow line, corresponding to those which are encountered in mean and high latitudes. The higher we ascend, the more does the number of the phænogamic class diminish in proportion to the cryptogamic, till only members of the latter family are found, whose further progress upward is arrested by the everlasting snow. The last lichen met with by Saussure on Mont Blanc, Silene acaulis, was also observed by M. Brevais in the neighbourhood of Bosekop, lat. 69 deg. 58 min. where it was vegetating on the seashore, shaded by the last pines of Europe.
1239. Isolated mountains display to the best advantage the effort of climatic change of vegetation.
1240. Etna is divided into three great regions: La Regione Culta, or fertile region; La Regione Sylvosa, or woody region; La Regione Deserta, the bare or desert region. But each of these is susceptible of sub-divisions, defined by the presence of certain families of plants, forming seven botanical zones.
1. The sub-tropical zone, which does not rise more than 100 feet above the level of the sea, is characterised by the palm, banana, Indian fig, sugar-cane, varieties of mimosa and acacia, which with us are only found in conservatories.
2. The hilly zone, rises about 2,000 feet, characterised by the orange, lemon, shaddock, maize, cotton, and grape plants.
3. The woody zone lies between the height of 2,000 and 4,000 feet, where the cork-tree flourishes, several kinds of oak, the maple, and enormous chestnuts.
4. The zone between the height of 4,000 and 6,000 feet is distinguished by the beech, Scotch fir, birch, and, among small plants, by clover, sandwort, chickweed, dock, and plantain.
5. The sub-alpine zone, between the elevation of 6,000 and 7,500 feet, produces the barberry, soap-wort, toad-flax, and juniper.
6. The zone between 7,500 and 9,000 feet, has almost all the plants of the preceding, with the fleshy and jagged groundsel.
"In the mountain of the height of Israel will I plant it; and it shall bring forth boughs, and bear fruit, and be a goodly cedar: and under it shall dwell all fowl of every wing; in the shadow of the branches thereof shall they dwell."—Ezekiel xvii.
7. The narrow zone between 9,000 and 9,200 feet, only produces a few lichens, beyond which, there is complete sterility.
1241. The Peak of Teneriffe exhibits five botanical districts, thus distinguished by Von Buch:
1. The region of Africa forms, 0—1,248 feet, comprising palms, bananas, the sugar-cane, various species of arborescent Euphorbiæ, Mesembryanthema, the Dracæna, and other plants, whose naked and tortuous trunks, succulent leaves, and bluish-green tints, are distinctive of the vegetation of Africa.
2. Region of Vines and Cereals, 1,248—2,748 feet, comprising also the olive, and the fruit-trees of Europe.
3. Region of Laurels, 2,748—4,350 feet, including lauri of four species, the wild olive, an oak, the iron-tree, the arbutus, and other evergreens. The ivy of the Canaries and various twining shrubs cover the trunks of the trees, and numerous species of fern occur, with beautiful flowering plants.
4. Region of the Pines, 4,350—6,270, characterised by a vast forest of trees resembling the Scotch fir, intermixed with juniper.
5. Region of the Retama, 6,270—11,061 feet, a species of broom, which forms oases in the midst of a desert of ashes, ornamented with fragrant flowers, and furnishing food to the goats, which run wild on the Peak. A few gramineous and cryptogamic plants are observed higher, but the summit is entirely destitute of vegetation.
1242. There are many plants which can accommodate themselves to the most diverse climates and localities; and therefore ascend from the plains close to the boundary of vegetable life on the highest mountains. But it is the general law in these cases for such plants to be singularly modified in appearance and anatomical structure as they ascend. The spring gentian, Gentiana verna, is one of the exceptions, which Raymond found unaltered at all heights in the Pyrenees.
1243. Trees, plants, and bushes, of humbler growth, which occur on the plains and at great heights, are usually much smaller in the latter situation. The leaves, and everything green about them, dwindle with the increased elevation; and the pure, well defined green is exchanged for an ill-defined light yellow. Singular enough, those parts which seem most capable of resisting cold, as the leaves and stalks, are uniformly subjected to a diminution of their vital functions; while the flowers remain of the same size, are never deformed, and become more dense and richer in their colours. While the Myosotis silvestris becomes stunted, its flowers assume an intense blue—the admiration of the traveller. The flowers of the pale primrose have a much deeper colour on the top of the Faulhorn, while the plant itself is much smaller than its congener on the Swiss plains. The observations of M. Parrot, among others, are to this effect on the flora of the Caucasus, of Ararat, the Swiss and Italian Alps, and the Pyrenees. The arctic flora is similarly distinguished.
1244. The preceding references to different climatic states are, however, perfectly inadequate to explain the phenomena of vegetable distribution. While an analogy is often observable between the plants of different regions under corresponding circumstances of latitude, elevation, and soil, the species are generally found to be different; and usually the botanical character of countries not widely apart from each other, is totally different, though un der the same parallels.
"From the rising of the sun, unto the going down of the same, the Lord's name is to be praised."—Psalm cxiii.
1245. Some plants are entirely confined to one side of our planet. The beautiful genus Erica, or heath, of which there are upwards of 300 species, occurs with breaks over a narrow surface, extending from a high northern latitude to the Cape of Good Hope. But the whole continent of America does not contain a single native specimen; nor has a Pœnia been found in it, except a solitary one to the west of the Rocky Mountains. On the other hand, the New World contains many families, as the Cacti, which are not found naturally in the Old.
1246. Some plants occur in a single specific locality, frequently a contracted area, and nowhere else. The beautiful Disa grandiflora is limited to a spot on the top of the Table Mountain at the Cape; and the celebrated cedar of Lebanon appears to be restricted in its spontaneous growth to the Syrian mountains. The small island of St. Helena has an indigenous flora, with a few exceptions different from that of the rest of the globe.
1247. Mountain chains of no great width very commonly divide a totally distinct botany. There is a marked difference in the vegetation of the Chilian and opposite side of the Andes, though the climate as well as the soil is nearly the same, and the difference of longitude very trifling. In North America, two completely different classes of vegetation appear on the two sides of the Rocky Mountains. A variety of oaks, palms, magnolias, azaleas, and magnificent rhododendrons occur on the eastern side, all of which are unknown on the western, the region of the giant pine.
1248. The distinct vegetation possessed by various parts of the globe, has led to its division into botanical kingdoms or phyto-geographical regions, named in general after the genera that are either peculiar to them, or predominant in them. The arrangement of M. Schouw, which is usually adopted, discriminates twenty-five great provinces of characteristic vegetation upon the surface of the earth.
In constituting any portion of the globe into a phyto-geographical region, M. Schouw has proceeded upon the following principles:—1. That at least one-half of the species should be indigenous in it. 2. That a-quarter of the genera should also be peculiar to it, or at least should have a decided maximum. 3. That individual families of plants should either be exclusively confined to the region, or have their maxima there.
1249. The phenomena of botanical geography, and the facts of geology, are mutually illustrative. The existing dry land having been upheaved above the waters at different epochs, it may be reasonably inferred that each portion on its emergence received a vegetable creation in harmony with its position. The ultimate constitution of the general surface into different botanical kingdoms would hence follow, each of which has preserved its primitive features, while adjoining, and even far distant foci, have to some extent intermingled their respective products, under control of the natural agencies of diffusion.
1250. The agents that involuntarily officiate in the diffusion of vegetable products are the atmosphere, the waters, and many animals.
1. The impulsion of the atmosphere in its calmest state, is quite sufficient to transport to considerable distances seeds furnished with downy appendages or winglets, as is the case with many plants, with the minute sporules of cryptogamia, which are light as the finest powder. When ordinary breezes convey the sand-dust of the Sahara a thousand miles or more from the desert, it may be conceived that seeds, which are comparatively heavy, are borne far from home by the hurricane. Two Jamaica lichens, which had never been seen in France before, were found by De Candolle growing on the coast of Brittany, the offspring of sporules which had been swept over the Atlantic.
"He shall come down like rain upon the mown grass, as showers that water the earth."—Psalm lxxii.
2. The mountain torrent washes down into the valley the seeds that have accidentally fallen into it, or have been swept away by its overflows; and hence the plants of the High Alps occur on the plains of Switzerland, which are entirely wanting in France and Germany. Rivers answer the same purpose more extensively, and also the oceanic currents. The nicker-tree, one of the leguminous tribe, has been raised from seed borne across the Atlantic by the Gulf stream.
3. Animals of the sheep and goat kinds, with the horse, deer, buffalo, and others, widely disperse several species of plants, the seeds of which, furnished with an apparatus of barbs and hooks, adhere to their coating. Seeds also of various kinds pass through the digestive organs of birds, uninjured as to their vitality. The little squirrel buries the acorn in the ground for winter provender, and sows an oak, if prevented from returning to the spot.
1251. Plants capable of extended naturalisation, and serviceable as articles of food or luxury, have been widely disseminated by the human race in their migrations. The cerealia afford a striking example. These important grasses known to the ancients, wheat, barley, oats, and rye, were the gifts of the Old World to the New. They are also importations into Europe; but the loose reports of the ancients, and the diligent researches of the moderns, alike leave us in ignorance of their native seat. Probability points to the conclusion that they have spread from the neighbourhood of the great rivers of Western Asia, the primitive location of the human family; and it is not impossible that in that imperfectly explored district, or further east on the Tartarian table-land, some of the cereals may yet be found growing spontaneously. The first wheat sown in North America, consisted of a few grains accidentally found by a negro slave of Cortes, among the rice taken for the support of his army. In South America the first wheat was brought to Lima by one of the early colonists, a Spanish lady, Maria d'Escobar. An ecclesiastic, Jose Rixi, was the first to sow it in the neighbourhood of Quito.
1252. Maize, or Indian corn (Zea mays), has been dispersed in the Old World from the New; and also a more important product, the potato (Solanum tuberosum), the use of which now extends from the extremity of Africa to Lapland. In Chili, the native country of the plant, it occurs at present in a wild state. The Spaniards imported it into Spain, and from thence it was communicated to Italy. It was first made known in England at a subsequent period from Virginia, having been received there from the Spanish colonists in South America, as it is not a native of intervening Mexico.
1253. The grape-vine, so extensively spread over Europe, is probably not indigenous in any part of it. It chiefly owes its diffusion there to the Romans, who received it from the Greeks, to whom it most likely immediately came from the country between the Black and Caspian Seas. The Romans introduced most of the finer European fruit-trees, some from Africa, as the pomegranate, but the great majority from Western Asia, as the or ange, fig, cherry, peach, apricot, apple, and pear. A variety of the plum, the damson, or damascene, came from the neighbourhood of Damascus during the Crusades. The name of the damask-rose points to the importation of the plant from the same quarter into Europe.
"To every thing there is a season, and a time to every purpose under heaven."—Ecclesiastes iii.
The ocean as well as the land has different botanical regions; and changes of the vegetation are observed with the depth analogous to the variations of terrestrial plants with the height. Marine vegetation seems to have its vertical extent determined by the range of light in water, which varies with the power of the sun and the transparency of the water.
CHAPTER LXIII.
1254. What are vegetable gums?
Vegetable gums are secretions of plants which are generally soluble in water, and which subserve various useful purposes. Gum Arabic is one of the most important of this class of vegetable productions.
Gutta-percha is an invaluable substance lately added to the list of known vegetable productions. It is obtained by cutting the bark of trees of the class called Sapotacea. Its proper name is gutta Pulo Percha, gutta meaning gum, and Pulo Percha is the island whence it is obtained. But gutta-percha is not, strictly speaking, a gum.
India-rubber is also a vegetable secretion, improperly called elastic gum. It is obtained from the milky juice of various trees and plants, especially from the syringe tree, of Cayenne.
1255. What are vegetable resins?
Vegetable resins are derived from the secretions of plants, and are generally distinguished from gums by being insoluble in water, but being soluble in spirits.
When one of these substances is soluble in either water or spirits it is called a gum-resin.
1256. What are vegetable acids?
Vegetable acids are chiefly obtained from fruit; but also abundantly from wood, by distillation.
"Thou art the God that doest wonders."—Psalm lxxvii.
Tannin is a vegetable production, obtained chiefly from the oak-bark, and from a variety of other vegetable sources. It possesses the peculiar chemical property which renders it valuable in tanning leather.
Opium is the produce of the poppy, and is obtained from the seed.
1259. What are vegetable dyes?
Vegetable dyes are the various colours derived from the secretions of plants, such as indigo, madder, logwood, alkanet-root, &c.
Silica is a mineral substance, commonly known as flint; and it is one of the wonders of the vegetable tribes, that, although flint is so indestructible that the strongest chemical aid is required for its solution, plants possess the power of dissolving and secreting it. Even so delicate a structure as the wheat straw dissolves silica, and every stalk of wheat is covered with a perfect, but inconceivably thin coating of this substance.
Amid all the wonders of nature which we have had occasion to explain, there is none more startling than that which reveals to our knowledge the fact that a flint stone consists of the mineralised bodies of animals, just as coal consists of masses of mineralised vegetable matter. The animals are believed to have been infusorial animalculæ, coated with silicous shells, as the wheat straw of to-day is clothed with a glassy covering of silica. The skeletons of animalculæ which compose flint may be brought under microscopic examination. Geologists have some difficulty in determining their opinions respecting the relation which these animalculæ bear to the flint stones in which they are found. Whether the animalculæ, in dense masses, form the flint; or whether the flint merely supplies a sepulchre to the countless millions of creatures that, ages ago, enjoyed each a separate and conscious existence, is a problem that may never be solved. And what a problem! The buried plant being disentombed, after having lain for ages in the bowels of the earth, gives us light and warmth; and the animalcule, after a sleep of ages, dissolves into the sap of a plant, and wraps the coat it wore, probably "in the beginning, when God created the heavens and the earth, and when the earth first brought forth living creatures," around the slender stalk of waving corn!
1261. Why is silica diffused over the stems of wheat, grasses, canes, &c.?
Because it affords strength, density, and durability, to structures that are very light, and which, but for this beautiful provision, would be exceedingly perishable.
"For in this mountain shall the hand of the Lord rest, and Moab shall be trodden down under him, even as straw is trodden down for the dunghill."—Isaiah xxv.
1262. Why is guano a productive manure?
Because it contains, with other suitable elements, an abundance of the silicous skeletons of animalculæ.
1263. Why does a wheat-crop greatly exhaust the soil?
Because, as well as the carbon, and the salts, which form the straw and the grain, it draws off from the soil a great amount of silica.
1264. Why is straw frequently used as a manure?
Because it gives back, with other substances, a considerable proportion of silica, in that form which adapts it to the use of the succeeding crop.
1265. Why is the structure of herbaceous plants less consolidated than that of woody plants?
Because, for the most part, herbaceous plants last only a single year; they, therefore, do not require the enduring qualities of plants that have to sustain the influences of the elements for a succession of seasons.
1266. Why are the stalks of plants of light structure generally cylindrical?
Because the cylindrical form is stronger than any other; a hollow cylinder, with moderately thick walls, is stronger than a solid rod, containing the same amount of material.
1267. Why do the stalks of plants become hollow?
Because the parallel and perpendicular fibres of the stalk are developed more rapidly than the horizontal. The growth of the plant, therefore, consists of a kind of divergence from the centre.
1268. Why are the stomata, or pores of leaves, generally placed on their under surface?
Because, being placed on the under surface, they are shaded from the action of the sun's rays, and so carry on the function of respiration more actively than if subjected to direct heat; they are also protected from the injurious effects of dust; and are moistened by evaporation from the earth's surface.
"The trees of the Lord are full of sap: and the cedars of Lebanon which he hath planted."—Psalm civ.
1269. Why have plants a formation of pith in their centre?
The pith is the chief organ of nutriment, especially in the young plant. It is the structure which first conveys fluids to, and receives them from, the newly-formed leaf. It communicates with every branch, leaf, bud, and flower; and also with the bark, through the medullary rays, which radiate horizontally from the centre of the plant. It is the centre of the movements of the sap which occur in the horizontal vessels; and it holds an important influence over the life of the plant.
1270. Why are trees covered with bark?
Because the bark serves to protect the woody structure, and also to give a passage to the descending sap which flows abundantly in the spring, and out of which the woody fibre is formed. It is also, from its peculiar nature, well fitted to endure the changes of the seasons for many years; and from its non-conducting properties it serves to maintain the equal temperature of the vital parts of the tree.
Cork is the bark of a description of oak-tree, which grows in great abundance in Spain, Italy, and France.
1272. Why does the cork-tree release its own bark?
Because it possesses a bark which is exceedingly useful to man; and it seems, therefore, to have been the design of providence that the tree should cast it off, to be applied to the wants of the human family; for the cork-tree does not discharge its bark by the mere cracking, or exfoliation, of its substance; the tree retains the bark for a number of years, until it has attained that consistency and thickness which renders it useful, and then the tree forms within the bark a series of tabular cells, which cut off the connection of the bark with the internal structure, after which it peels off in large sheets.
"And all the trees of the field shall know that I the Lord have brought down the high tree, have exalted the low tree, have dried up the green tree, and have made the dry tree to flourish: I the Lord have spoken, and have done it."—Ezek. xvii.
Man assists this evident intention of nature, by slitting the bark from the top of the tree to its base; but even were this not done, the bark would be cast off by the tree itself.
Another proof of design in this useful adaptation of the cork-tree is to be found in the fact, that it thrives under treatment that would destroy other trees. The cork-tree will endure the barking process for seven or eight successive years.
CHAPTER LXIV.
1273. Why are there curious markings in walnut, mahogany, rose-wood, satin-wood, &c.?
Because those markings are produced by the various structure of the vessels by which the wood is formed; and by successive zones of wood, which indicate the periods of growth.
The inclosure of zone within zone is owing to the mode in which the wood is produced, and the position in which it is deposited. Wood is formed by the leaves during the growing season, and passes down towards the root between the bark and the wood of the previous year (if any), or in the position in which cambium is effused; and, as the leaves more or less surround the whole stem, the new layer at length completes a zone, and perfectly encloses the wood of all former years. This is the explanation of the term exogenous, which is derived from two words signifying to grow outwardly, for the stem increases in thickness by successive layers on the outer side of the previously-formed wood. That this is the mode of growth has been abundantly proved by experiment, and demonstrated by accidental discoveries. Thus, if a plate of metal be inserted between the bark and wood, it will, in progress of time, become inclosed by the new wood which has overlaid them. So in like manner if letters be cut deeply through the bark and into the wood, the spaces will not be filled up from the bottom, but may be seen in subsequent years overlaid by new wood. A statement appeared in a daily paper, during the past year, to the effect that in cutting down a tree a cat had been discovered inclosed in the wood of the trunk. These facts prove that the wood is applied from without. Again, if a branch be stripped of its leaves down to a certain point, it will not grow above that point; and so, in like manner, if branches be stripped from one side of a tree, the tree will not grow on that side. If a circle of bark be removed from a branch above and also below a leaf, it will be found that increase of size will occur below, but not above that bud; and so, likewise, whenever a ring of bark is removed from a tree, the new woody fibre will not proceed from the lower but from the upper edge.—Orr's Circle of the Sciences.
"And when he saw a fig tree in the way, he came to it, and found nothing thereon, but leaves only, and said unto it, Let no fruit grow on thee henceforward for ever. And presently the tree withered away."—Matthew xxi.
1274. Why have trees with large trunks a great number of leafy branches?
Because it is by the leaves that the secretion is formed which supplies the woody fibre. The number of leaves on a tree, therefore, generally bears a relation to the size of its trunk, and the number of its branches.
1275. Why have poplar-trees comparatively few branches and leaves?
Because their trunks are comparatively small, although they grow to a great height.
1276. Why had the mammoth-tree comparatively few leaves in relation to the immense size of its bark?
Because the woody texture of this tree (Wellingtonea gigantea) is exceedingly light and porous. It is, in fact, lighter than cork, and, therefore, requires less leaf-produce in its formation.
1277. Why have oak-trees an abundance of leaves?
Because their wood is so dense that they require a larger amount of the wood-forming secretion which is supplied by the leaves.
1278. Why are the trunks of trees round?
Because, generally speaking, the leaves are distributed upon branches around the trees in every direction. They consequently send down the wood-forming principle on all sides. When a trunk is unduly developed on one side, it may generally be traced to the unequal distribution of the branches.
1279. What are exogenous stems?
Exogenous stems are those that grow by the addition of wood on their outer surface, underneath the bark.
1280. What are endogenous stems?
Endogenous stems are those that grow inwardly, from the centre. Trees of this class, of which palms are the best example, are almost peculiar to tropical climates.
1281. Why do endogenous stems chiefly abound in tropical climates?
Because, probably, the excessive heat of those climates would interfere with the formation of wood from the sap upon the outer surface.
The vascular structure of endogenous stems lying more abundantly towards their centre, tends to conserve the juices which in hot climates are so highly valued. Palm-wine is a delicious and cooling beverage, and is procured from various kinds of palms, but especially from the cocoa-nut palm. Even the fresh sap is very refreshing. The juice is procured by cutting the tree in the upper part, and attaching a vessel to the opening, to receive the sap. Its flow is increased by cutting off a slice of the wood daily.
"I have caused thee to multiply as the bud of the field, and thou hast increased and waxen great, and thou art come to excellent ornaments."—Ezekiel xvi.
1282. Why have endogenous stems no bark?
Because, one of the chief functions of the bark in exogenous trees, is to protect the sap from which the wood is formed on the outward surface; and as there is no such external flow of sap in endogenous trees, the bark is unnecessary to them, and is therefore withheld. They are furnished instead with a thin cuticle.
1283. Why do endogenous stems grow to a great height?
Because, as the stem grows from the centre, it soon reaches that limit of diameter which its vascular structure is calculated to support; and, therefore, the wood-forming sap is deposited chiefly at the top of the stem, causing it to grow to a considerable height.
1284. Why do the various vegetable fruits ripen in succession?
Because the Author of Nature has thus arranged its economy, in order that the wants of living creatures may be adequately provided for. Some vegetable productions arrive at their perfection in the spring; others in summer; and others in autumn. Among the latter are many that require to come slowly to maturity after they are gathered; by these the winter season is provided for, and a surplus of the winter stock goes to supply the natural deficiency of spring.
"O sing unto the Lord a new made song; for he hath done marvellous things."—Psalm xcviii.
1285. Why, when seeds are sown, and germination begins, does the leaf-germ seek the light, and the root-germ grow down into the earth?
Because the Creator has endowed every single seed with a vital instinct which governs its development. The rootlet could more easily grow upward than downward, because of the looser earth, and of the exciting influences of light and moisture. Yet it takes the contrary course, leaving the leaf-germ to come up to meet the sun-light, and to send down to the stem and roots, the matter needed for their growth.
Frequently, indeed, when seeds are thrown into the earth, their natural position is reversed, and when the germs first start from the seed, the root-germ is directed upward and the leaf-germ downward. What then occurs? They each turn, and, in doing so, frequently cross each other. Each goes to its particular duty—the duty that God appointed.
CHAPTER LXV.
1286. Why are the seeds of plants indigestible?
Because they are encased in a hard covering upon which the gastric juice of animals takes no effect. This provision has been made by the Creator, for the preservation of seeds, the productions of which are so essential to animal life.
The gastric juice can dissolve any other part of the plant, even the woody fibre, and yet upon the seed it takes no effect. When, however, the seed is crushed, and, thereby, the vital principle destroyed, so that no plant can spring from it, the gastric juice acts upon it, and it is soon dissolved.
Hence graminivorous birds are provided with gizzards to break the protecting coats of the grain; and animals that feed on seeds and nuts strip them of their shells and husks.
It is remarkable that in the succulent fruits, such as the strawberry, the raspberry, currant, apple, orange, melon, &c., and which, from their very nature, are likely to attract animals to use them, and in eating which the seeds are likely to be swallowed, they are fortified by a doubly-protective coating; the pips of the apple, orange, &c., and the seeds of the strawberry and raspberry, pass through the digestive organs, not only unharmed, but their germinating powers are even improved by the warmth and trituration of the stomach. Indeed, the stomachs of quadrupeds and birds have been made the vehicles of propagating plants, and distributing them to the widest geographical latitudes. It is even said of some seeds that they will not germinate until they have passed through the digestive organs of an animal.
"And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree."—Revelation ix.
1287. Why do animals that graze, crop the tender blades of grass, but avoid the tall stems?
Because they are tempted by the greater sweetness and tenderness of the young blades; and in this temptation a very important end is served; for, by avoiding the stems that have grown up, the animals spare the matured plant by which seeds are borne, and by which the supply of food is to be continued.
1288. Why do the eggs of butterflies lie dormant during the winter?
Because the coldness of the winter would be fatal to the life of the young insects; and the absence of vegetation would leave the caterpillars to perish of starvation, if they were developed during the winter months.
Fig. 76.—CATERPILLAR FEEDING.
1289. Why do caterpillars appear in the spring?
Because the increasing warmth of the sun developes the living embryo, at the same time that it developes the vegetable germ. The warmth, therefore, that calls the caterpillar from its embryo sleep, also kindles the germinating power of the vegetable upon which it is destined to feed. The worm awakes and finds the bountiful table of nature spread for it.
"Thou shalt plant vineyards, and dress them, but shalt neither drink of the wine, nor gather the grapes: for the worms shall eat them."—Deuteronomy xxviii.
1290. Why does the caterpillar eat voraciously?
Because it grows rapidly, and a large amount of vegetable matter is necessary to supply the rapid growth of its animal substance. Caterpillars in the course of a month devour 60,000 times their own weight of aliment.
Fig. 77.—THE UNDER SIDE OF THE CHRYSALIS OF THE PEACOCK BUTTERFLY.
Fig. 78.—THE SAME CHRYSALIS, WITH PART OF ITS SHEATH RAISED TO SHOW THE PARTIALLY-FORMED WINGS, &c.
1291. Why do caterpillars pass into the state of the chrysalis?
Because they are thereby prepared for the new existence which they are about to enjoy; new organs must be perfected in them to adapt them to the altered conditions of their lives.
Because, also, in the transformation of their bodies, differing materially from the laws of existence that pertain to other creatures, the Creator affords another illustration of his Omnipotence.
Because, also, during the stage that the insect sleeps in the chrysalis, the flowers and their sweet juices, upon, which the fly is to feed, are being prepared for it, just as, when it was sleeping in the egg, the green food was being prepared for the caterpillar. When, therefore, the beautiful fly spreads its silken wings, it finds a second time that, while it has slept, its meal has been prepared, and it now flies away joyously to feed upon the milk and honey of beautiful flowers which, at the time it passed into the chrysalis, had not yet unfolded their petals.
"For the moth shall eat them up like a garment, and the worm shall eat them like wool: but my righteousness shall be for ever, and my salvation from generation to generation."—Isaiah li.
Fig. 79.—THE PEACOCK BUTTERFLY.
Paley observes, that "the metamorphosis of insects from grubs into moths and flies, is an astonishing process. A hairy caterpillar is transformed into a butterfly. Observe the change. We have four beautiful wings where there were none before; a tubular proboscis, in the place of a mouth with jaws and teeth; six long legs, instead of fourteen feet. In another case, we see a white, smooth, soft worm, turned into a black, hard, crustaceous beetle, with gauze wings. These, as I said, are astonishing processes, and must require, as it should seem, a proportionably artificial apparatus. The hypothesis which appears to me most probable, is that, in the grub, there exists at the same time three animals, one within another, all nourished by the same digestion, and by a communicating circulation; but in different stages of maturity. The latest discoveries made by naturalists, seem to favour this supposition. The insect, already equipped with wings, is descried under the membranes both of the worm and nymph. In some species, the proboscis, the antennæ, the limbs, and wings of the fly, have been observed to be folded up within the body of the caterpillar; and with such nicety as to occupy a small space only under the two first wings. This being so, the outermost animal, which, besides its own proper character, serves as an integument to the other two, being the farthest advanced, dies, as we suppose, and drops off first. The second, the pupa or chrysalis, then offers itself to observation. This also, in its turn, dies; its dead and brittle husk falls to pieces, and makes way for the appearance of the fly or moth. Now, if this be the case, or indeed whatever explication be adopted, we have a prospective contrivance of the most curious kind; we have organisations three deep; yet a vascular system, which supplies nutrition, growth, and life, to all of them together."
"That which the palmer-worm hath left hath the locust eaten; and that which the locust hath left hath the canker-worm eaten; and that which the canker-worm hath left hath the caterpillar eaten."—Joel i.
Lord Brougham, in a note upon the above, does not support Paley's view. He says "It is more than probable that the parts which are to appear in the perfect insect do not exist in the larvæ, where there is not much difference between the larva and pupa, excepting at the time just previous to its becoming a pupa, at which time the larva is motionless and torpid. The caterpillar of a moth, when about to turn into a pupa, provides for the protection of the latter state, either by surrounding itself with a web, or by some other means. Soon after this is accomplished, the caterpillar becomes motionless, or nearly so; it can neither eat nor crawl. At this time, and not before, the parts of the pupa are forming within the skin of the caterpillar, which may be easily seen by dissection."
It appears to the author, however, that Paley is partially right, and Lord Brougham totally wrong, in these remarks. When Lord Brougham asserts that the parts of the pupa are forming within the skin of the caterpillar at that time when the transformation begins, "and not before, which may be easily seen by dissection," he forgets, that although in some instances it is the first moment when, to the human eye, the organs of the new creature become perceptible, that the "three deep" nature which Paley attributes to the grub, must really have existed in the egg—that the butterfly originated in the egg, as certainly as did the caterpillar, or the chrysalis, and that unless that egg had possessed its three mysterious embryos, it would have been impossible for the grub to have progressed to the stages of transformation. No one has ever known the embryo of a bird's egg to pass through three distinct and dissimilar states of existence; nor has any one ever known the embryo of the butterfly's egg to stop short at either of the stages, if the proper conditions of its existence and development were supplied to it. Why? Because the embryo of the insect has a threefold nature, while that of the bird is single.
"They shall cut down her forest, saith the Lord, though it cannot be searched; because they are more than the grasshoppers, and are innumerable."—Jeremiah xlvi.
CHAPTER LXVI.
1292. Why does the caterpillar become torpid when passing into the state of the chrysalis?
Because in all probability, where the difference between the first and the ultimate form is considerable, the organs of the insect having to undergo great changes, it would suffer considerable pain. Torpor comes upon the insect, it is thrown into a state similar to that of a person who has inhaled chloroform; and after what has, in all probability, proved a pleasant dream, the insect awakes to find itself changed and beautified.
1293. Why are the pupæ of grasshoppers and other insects, when about to undergo transformation, still active and sensitive?
Because, as there is but a slight difference between the form which they have in the pupa state, and that which they ultimately assume, they do not require the state of torpidity to save them from pain, nor to arrest their movements while their organs are being changed. With them the outer skin is thrown off, and they are then perfect insects.
1294. Why do caterpillars, when about to pass through the chrysalis state, attach themselves to the leaves of plants, &c.?
Because they know instinctively that for a time they will be unable to controul their own movements, and to avoid danger. They therefore choose secure and dry places, underneath leaves, or in the crevices of old and dry walls, and there they firmly attach themselves, to await the time of their liberation.
1295. Why do insects attach their eggs, to leaves &c.?
Because, as the eggs have to be preserved during the winter, the insect attaches them to some surface which will be a protection to them. Generally speaking, the eggs are attached to the permanent stems of plants, and not to those leafy portions which are liable to fall and decay. The spider weaves a silken bag in which it deposits its eggs, and then it hangs the bag in a sheltered situation. Nature keeps her butterflies, moths, and caterpillars, locked up during the winter, in their egg-state; and we have to admire the various devices to which, if we may so speak, the same nature has resorted for the security of the egg. Many insects enclose their eggs in a silken web; others cover them with a coat of hair, torn from their own bodies; some glue them together; and others, like the moth of the silk-worm, glue them to the leaves upon which they are deposited, that they may not be shaken off by the wind, or washed away by rain; some again make incisions into leaves, and hide an egg in each incision; whilst some envelope their eggs with a soft substance, which forms the first aliment of the young animal; and some again make a hole in the earth, and, having stored it with a quantity of proper food, deposit their eggs in it.
"Lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through and steal."—Matt. vi.
1296. Why do butterflies fly by day?
Because they are organised to enjoy light and warmth, and they live upon the sweets of flowers which by day are most accessible.
1297. Why do moths fly by night?
Because they are organised to enjoy subdued light and cool air; and as they take very little food during the short life they have in the winged state, they find sufficient by night. Some of the moths, like that of the silk-worm, take no food from the time they escape from the chrysalis until they die.
Because, also, they form the food of bats, owls, and other of the night-flying tribes.
1298. Why are the bodies of moths generally covered with a very thick down?
Because, as they fly by night, they are liable to the effects of cold and damp. The moths, therefore, are nearly all of them covered with a very thick down, quite distinguishable from the lighter down of butterflies.
1299. Why do moths fly against the candle flame?
Because their eyes are organised to bear only a small amount of light. When, therefore, they come within the light of a candle, their sight is overpowered and their vision confused; and as they cannot distinguish objects, they pursue the light itself, and fly against the flame.
"Let him that glorieth glory in this that he understandeth and knoweth me, that I am the Lord which exercise loving-kindness, judgment, and righteousness in the earth: for in these things I delight, saith the Lord."—Jer. ix.
1300. Why do insects multiply so numerously?
Because they form the food of larger animals, and especially of birds. A single pair of sparrows and a nest of young ones have been estimated to consume upwards of three thousand insects in a week.
1301. Why does the "death-watch" make a ticking noise?
Because the insect is one of the beetle tribe, having a horny case upon its head, with which it taps upon any hard substance, the ticking is the call of the insect to its species, just as the noise made by the cricket is a note of communication with other crickets.
There is a superstition connected with the death-watch, which, like most superstitions, is based upon the theory of probabilities. The death-watch is usually heard in the spring of the year, and a superstition runs to the effect that some one in the house will die before the year has ended. Persons who are superstitious are never very strict in the interpretation of their predictions; and therefore, whether a person dies in the house or out of it, in the same room where the death-watch was heard, or across the wide Atlantic, so that there be some kind of relationship, or even acquaintance, between the person who hears the omen, and the person dying, the event is sure to be connected with the prophetic sounds of the death-watch. Little weens the small timber-boring beetle, when he is tapping gently to call his mate, and perhaps peeping into every corner and crevice to find her, that he is sending dismay into the heart of some superstitious listener, who, in ignorance of a simple fact, overwhelms herself with an imaginary grief.
1302. Why are insects in the first stage, after leaving the egg, said to be in the "larva" state?
Because the term larva is derived from the Latin larvated, meaning masked, clothed as with a mask; the term is meant to express that the future insect is disguised in its first form.
1303. Why are insects in the second state said to be in the "pupa" state?
Because the term is derived from the Latin pupa, from a slight resemblance in the manner in which the insects are enclosed, to that in which it was the fashion of the ancients to bandage their infants.
1304. Why are insects in the "pupa" stage also called "chrysalides?"
Because, as the Latin term implies, it is adorned with gems. Many chrysalides are studded with golden and pearl-like spots.
"Thou hast set all the borders of the earth: thou hast made summer and winter."—Psalm lxxiv.
1305. Why are the perfect insects said to be in the "nymph" state?
Because their joyful existence, and their beautiful forms, give them a fancied resemblance to the nymphs of the heathen mythology. The nymphs were supposed goddesses of the mountains, forests, meadows, and waters.
This term has generally, but very improperly, been also applied to the pupa state, so that pupa, chrysalis, and nymph have all been employed to represent one state. This is obviously an error, as there is nothing in the condition of the pupa or chrysalis that can at all accord with the mythological idea of a nymph, and which, in reference to the beautiful and joyous fly, finds a much truer application.
CHAPTER LXVII.
1306. Whence does the snail obtain its shell?
Young snails come from the egg with a shell upon their backs.
1307. How does the shell grow with the increase of size of the animal?
The soft slime which is yielded by the body of the animal, hardens upon the orifice of the shell, and thus increases its size.
Fig. 80.—COMMON GARDEN SNAIL.
1308. Why is the shell spiral?
Partly because of its original formation; but also because, as the shell grows, the opening is elongated; and thrown up, causing the spiral body of the shell to turn, and so to wind its growth around the centre.
"Notwithstanding they hearkened not unto Moses; but some of them left it until the morning, and it bred worms, and stank: and Moses was wrath with them."—Exodus xvi.
1309. Why has the snail four tentacula attached to its head?
Because the insect, having no other limbs, is provided with those projecting members, the lower two serving as feelers and the upper two also as feelers and eyes. These, projecting in the front of the animal, impart to it a consciousness of surrounding objects, and especially of those which lie in its path.
1310. Why is the snail able to move, without feet?
Because it has attached to its body a fringe of muscular skin, which is capable of considerable contraction and expansion, and by alternately stretching and shortening this, the snail is able to draw himself along.
1311. Why do we see no snails in the winter time?
Because they bury themselves in the ground, or in holes, where they remain in a torpid state for several months. Before they enter into the torpid state, they form with their slimy secretion, and with some earthy matters which they collect, a strong cement with which they seal up the opening to their shells.
1312. Why can snails live in shells thus sealed?
Because they leave, in the thin wall by which they close themselves in, a small hole, too small to admit water, but large enough to let in sufficient air to carry on their feeble respiration during their winter sleep.
1313. Why do insects abound in putrid waters, and in decaying substances?
Because they have been endowed with appetites and with constitutions that enable them to live upon and to enjoy corrupt matter. In this point of view the maggots of flies are exceedingly useful; a dead carcass is speedily threaded by them in every direction; thus that corrupt matter which, in a large mass, would poison the air, is taken up in small portions by millions of living bodies, and by them dispersed, and becomes innoxious.
"For he maketh small the drops of water: they pour down rain according to the vapour thereof."—Job xxxv.
1314. Why do we see, in tanks of rain water, insects rising to the surface?
Because numerous insects pass through their first stages of existence in water, and among them the common gnat. The gnats of the previous season having deposited their eggs on the sides of the water-butt, the warm water developes them, and the larvæ of the gnats appear ([Fig. 81]; c natural size of larva; b larva magnified).
![[Fig. 81]](#i-340.jpg){kind=link}
Fig. 81.—LARVA AND PUPA OF GNAT.
(Greatly magnified.)
1315. Why do they continually rise to the surface of the water?
Because they require to breathe air, and therefore they come up to the surface, where, elevating the tube (b) above the surface of the water, they are enabled to breathe.
1316. Why do some appear to have larger heads than others?
Those that have apparently larger heads, and that breathe through tubes attached to their heads (d) are in the pupa, or second stage of development, and underneath the large shield by which their heads are marked, their wings, feet, &c., are being formed.
"Because thy loving kindness is better than life, my lips shall praise thee."—Psalm lxiii.
1317. Why, when the water is disturbed, do the larvæ descend more rapidly than the pupæ?
Because the pupæ are in a torpid condition, awaiting the formation of their perfect organs.
1318. Why are the flies able to escape from the water?
Because, as their formation becomes perfected, and the fluids of the body of the pupa become absorbed in the production of the light texture of the wings, &c., the body and its case become lighter than the water, and rise and float upon the surface. The pupa-case then forms a natural boat, from which the fly emerges, and spreading its wings, enters upon the final state of its existence.
Fig. 82.—THE PERFECT GNAT. ESCAPING FROM THE PUPA-CASE.
(Greatly magnified.)
This interesting metamorphosis may be seen going on in the summer time, in every pond, brook, and reservoir. A fine sunny morning calls up millions of these little boats from beneath the surface, and the diver within that wonderful little bell breaks its sealed doors, and flies away to enjoy the bright sunshine.
1319. Why are beetles denominated "coleoptera?"
Because they have wings protected by horny sheaths; the term coleoptera signifies wings in a sheath.
"They shall lie down in the dust; and the worms shall cover them."—Job xxi.
1320. Why have beetles hard horny wing-cases?
Because they live underground, or in holes excavated in wood, &c. If, therefore, their wings were not protected by a hard and firm covering, they would be constantly liable to destruction from the movement of the insect within hard and rough bodies.
Fig. 83.—STAG-BEETLE, SHOWING ITS WINGS UNFOLDED, AND THE WING-CASES OPEN.
The elytra, or scaly wings of the genus of scarabæus, or beetle, furnish an example of this kind. The true wing of the animal is a light, transparent membrane, finer than the finest gauze, and not unlike it. It is also, when expanded, in proportion to the size of the animal, very large. In order to protect this delicate structure, and, perhaps, also to preserve it in a due state of suppleness and humidity, a strong, hard case is given to it, in the shape of the horny wing which we call the elytron. When the animal is at rest, the gauze wings lie folded up under this impenetrable shield. When the beetle prepares for flying, he raises the integument, and spreads out his thin membrane to the air. And it cannot be observed without admiration, what a tissue of cordage, i. e. of muscular tendons, must run in various and complicated, but determinate directions, along this fine surface, in order to enable the animal, either to gather it up into a certain precise form, whenever it desires to place its wings under the shelter which nature hath given to them, or to expand again their folds when wanted for action.
"The Lord is good; his mercy is everlasting; and his truth endureth to all generations."—Psalm c.
In some insects, the elytra cover the whole body; in others, half; in others only a small part of it; but in all, they completely hide and cover the true wings. Also,
Many, or most of the beetle species lodge in holes in the earth, environed by hard, rough substances, and have frequently to squeeze their way through narrow passages; in which situation, wings so tender, and so large, could scarcely have escaped injury, without both a firm covering to defend them, and the capacity of folding themselves up under its protection.
1321. Why have many of the beetle tribe large strong horns?
Because, as they live in holes in the earth, or in excavations in wood, they use their horns to dig out their places of retreat.
1322. Why has the giraffe a small head?
Because, being set upon the end of a very long neck, the animal would be unable to raise it if it were heavy.
1323. Why has the giraffe a long neck?
Because it feeds upon the branches of tall trees.
1324. Why has the giraffe a long and flexible tongue?
Because it is thereby enabled to lay hold of the tender twigs and branches, and draw them into its mouth, avoiding the coarser parts of the branches.
1325. Why are the nostrils of the giraffe small and narrow, and studded with hairs?
Because the hairs and the peculiar shape of the nasal passages are designed as a protection against the insects which inhabit the boughs of the trees upon which the giraffe feeds; and also against the sands of the desert, which storms raise into almost suffocating clouds.
"Bless the Lord, all his works, in all places of his dominion: bless the Lord, O my soul."—Psalm ciii.
Fig. 84.—GIRAFFE FEEDING.
1326. The distribution of animals, or Zoological Geography, is of great interest, and should be carefully studied in connection with Botanical Geography (see [1208]). The highest department of the animal kingdom (writes the Rev. W. Milner) commences with the class of Birds, which may be naturally divided into the three great orders of ærial, terrestrial, and aquatic. Aggregation into immense flocks is a distinguishing feature of several species, especially of the aquatic order, which form separate colonies, building their nests in the same state, though other spots equally adapted are at no great distance. Hence the Vogel-bergs, or bird rocks of the northern seas, one of which at Westmannsharn in the Faroe group of islands, seldom intruded upon by man, presents a most extraordinary spectacle to the visitor. The Vogel-berg lies in a frightful chasm in the precipitous shores of the island, which rise to the height of a thousand feet, only accessible from the sea by a narrow passage. Here congregate a host of birds. Thousands of guillemots and auks swim in groups around the boat which conveys man to their domain, look curiously at him, and vanish beneath the water to rise in his immediate neighbourhood. The black guillemot comes close to the very oars. The seal stretches his head above the waves, not comprehending what has disturbed the repose of his asylum, while the rapacious skua pursues the puffin and gull. High in the air the birds seem like bees clustering about the rocks, whilst lower they fly past so close that they might be knocked down with a stick. But not less strange is the domicile of this colony. On some low rocks scarcely projecting above the water sit the glossy cormorants, turning their long necks on every side. Next are the skua gulls, regarded with an anxious eye by the kittiwakes above. Nest follows nest in crowded rows along the whole breadth of the rock, and nothing is visible but the heads of the mothers and the white rocks between. A little higher on the narrow shelves sit the guillemots and auks, arranged as on parade, with their white breasts to the sea, and so close that a hailstone could not pass between them. The puffins take the highest station, and, though scarcely visible, betray themselves by their flying backwards and forwards. The noise of such a multitude of birds is confounding, and in vain a person asks a question of his nearest neighbour. The harsh tones of the kittiwakes are heard above the whole, the intervals being filled with the monotonous note of the auk, and the softer voice of the guillemot. When Graba, from whose travels this description is principally drawn, visited the Vogel-berg, he was tempted by the sight of a crested cormorant to fire a gun, but what became of it, he remarks, it was impossible to ascertain. The air was darkened by the birds roused from their repose. Thousands hastened out of the chasm with a frightful noise, and spread themselves over the ocean. The puffins came wandering from their holes, and regarded the universal confusion with comic gestures. The kittiwakes remained composedly in their nests, whilst the cormorants tumbled headlong into the sea. Similar great congregations of the feathered race appear where the shores are rocky high, and precipitous, but this is strikingly the case, where
——"The northern ocean, in vast whirls,
Boils round the naked melancholy isles
Of farthest Thule; and the Atlantic surge
Pours in among the stormy Hebrides.
Who can recount what transmigrations there
Are annual made? what nations come and go?
And how the living clouds on clouds arise?
Infinite wings! till all the plume-dark air
And rude resounding shore are one wild cry."
"He rained flesh upon them as dust, and feathered fowls like as the sand of the sea."—Psalm lxxviii.
1327. Most terrestrial birds, unacquainted with man, exhibit a remarkable tameness, and are slow in acquiring a dread of him, even after repeated lessons that danger is to be apprehended from his neighbourhood. Mr. Darwin speaks of a gun as almost superfluous in the unfrequented districts of South America, for with its muzzle he pushed a hawk off the branch of a tree. Once, while lying down, a mocking thrush alighted on the edge of a pitcher, made of the shell of a tortoise, which he was holding in his hand, and began very leisurely to sip the water, even allowing him to handle it while seated on the vessel. In Charles Island, which had been colonised about six years, he saw a boy sitting by a well with a switch in his hand, with which he killed the doves and finches as they came to drink; and for some time had been constantly in the habit of waiting by the well for the same purpose, to provide himself with his dinners. In the Falkland Islands, at Bourbon, and at Tristan d'Acunha, the same tameness was noticed by the early visitors. On the other hand, the small birds in the arctic regions of America, which have never been persecuted, exhibit the anomalous fact of great wildness. From a review of various facts, Mr. Darwin concludes, "first, that the wildness of birds with regard to man is a particular instinct directed against him, and not dependent on any general degree of caution arising from other sources of danger; secondly, that it is not acquired by individual birds in a short time, even when much persecuted; but that in the course of successive generations it becomes hereditary. Comparatively few young birds in any one year have been injured by man in England, yet almost all, even nestlings, are afraid of him; many individuals, however, both at the Galapagos and at the Falklands, have been pursued and injured by man, but yet have not learned a salutary dread of him."
"As a bird that wandereth from her nest; so is a man that wandereth from his place."—Psalm xxvii.
1328. Numerous species of birds may be regarded as the favourites of nature on account of the gracefulness given to their shape, and the richly-coloured plumage with which they are adorned, as evidenced in the gaudy liveries of many of the parrot tribe, and the forms and hues of the birds of paradise. But they are especially interesting to man for the faculty of song with which they are endowed; in some, "most musical, most melancholy," in others, sprightly and animating, inspiriting the sons of toil under the burdens peculiar to their station. It deserves to be remarked, as an instance of compensation and adjustment, that whilst the birds of the temperate zone are far inferior to those of tropical climes in point of beauty, they have far more melodious notes in connection with their less attractive appearance.
1329. From the powerful means of locomotion possessed by several of the bird tribe, and their great specific levity, air being admitted to the whole organisation as water to a sponge, it might be inferred, that the entire atmosphere was intended to be their domain, so that no species would be limited to a particular region. The common crow flies at the rate of twenty-five miles an hour; the rapidity of the eider-duck, Anas mollissima, is equal to ninety miles an hour; while the swifts and hawks travel at the astonishing speed of a hundred and fifty miles in the same time. It is true that some species have a very extensive range, as the nightingale, the common wild goose, and several of the vulture tribe. The same kind of osprey or fishing-eagle that wanders along the Scottish shores appears upon those of the south of Europe, and of New Holland. The lammergeyer haunts the heights of the Pyrenees, the mountains of Abyssinia, and the Mongolian steppes; and the penguin falcon occurs in Greenland, Europe, America, and Australia. In general, however, like plants and terrestrial quadrupeds, the birds are subject to geographical laws, definite limits circumscribing particular groups. The common grouse of our own country affords a striking exemplification of this arrangement, as it is nowhere met with out of Great Britain; and other examples occur of a very scanty area containing a species not to be found in any other region. The celebrated birds of paradise we exclusively confined to a small part of the torrid zone, embracing New Guinea and the contiguous islands; and the beautiful Lories are inhabitants of the same districts, being quite unknown to the New World. Parroquets are chiefly occupants of a zone extending a few degrees beyond each tropic, but the American group is quite distinct from the African, and neither of these have one in common with the parrots of India. The great eagle is limited to the highest summits of the Alps; and the condor, which soars above the peak of the loftiest of the Andes, never quits that chain. Humming-birds are entirely limited to the western hemisphere, where a particular species is sometimes bounded by the range of an island, while others are more extensively spread, the Trochilus flammifrons, common to Lima, being observed by Captain King upon the coast of the Straits of Magellan, in the depth of winter, sucking the flowers of a large fuchsia, then in bloom in the midst of a shower of snow. Among the birds incapable of flight, which rival the quadrupeds in their size, the intertropical countries of the globe have their distinct species, presenting similar general features of organisation, as the ostrich of Africa and Arabia, the cassowary of Java and Australia, and the touyou of Brazil. In the arctic regions, we meet with species peculiar to them, the Strix laeponicus or Lapland owl, and the eider-duck, an inhabitant of the shores, from whose nests the eider-down is obtained. Several families of maritime birds are likewise limited to particular oceanic localities. Approaching the fortieth parallel of latitude, the albatross is seen flitting along the surface of the waves, and soon afterwards the frigate and other tropical birds appear, which never wander far beyond the torrid zone. It thus appears, that, notwithstanding the great locomotive powers of birds, particular groups have had certain regions assigned to them as their sphere of existence, which they are adapted to occupy, and to which they adhere in the main, though it is easy to conceive of natural causes occasionally constraining to a migration into new and even distant territories. Captain Smyth informed Mr. Lyell, that when engaged in his survey of the Mediterranean, he encountered a gale in the Gulf of Lyons, at the distance of between twenty and thirty leagues from the coast of France, which bore along many land-birds of various species, some of which alighted on the ship, while others were thrown with violence against the sails. In this manner, many an islet in the deep, after ages of solitude and silence, uninterrupted except by the wave's wild dash, and the wind's fierce howl, may have received the song of birds, forced by the tempest from their home, and compelled to seek a new one under its direction.
"There is a path which no fowl knoweth, and which the vulture's eye hath not seen."—Job xviii.
1330. There is no feature more remarkable in the economy of birds than the periodical migrations, so systematically conducted, in which five-sixths of the whole feathered population engage. In the case of North America, according to an estimate by Dr. Richardson, the passenger-pigeons form themselves into vast flocks for the journey, one of which has been calculated to include 2,230,000,000 individuals. We are familiar with the cuckoo as our visitor in spring, and with the house-swallow as our guest through the summer, the latter usually departing in October to the warmer regions of the south, wintering in Africa, returning again when a more genial season revives its insect food. By cutting off two claws from the feet of a certain number of swallows, Dr. Jenner ascertained the fact of the same individuals re-appearing in their old haunts in the following year, and one was met with even after the lapse of seven years. The arctic birds migrate farther south, when the seas, lakes, and rivers become covered with unbroken sheets of ice; the swans, geese, ducks, divers, and coots flying off in regular phalanxes to regions where a less rigorous winter allows of access to the means of life. Hence, soon after, we lose the swallows, we gain the snipes and other waders, which have fled from the hard frozen north to our partially frozen morasses, where their ordinary nutriment may still be obtained. The equinoctial zone, where the seasonal change is that of humidity and drought furnishes an example of the same phenomenon. As soon as the Orinoco is swollen by the rains, overflows its banks, and inundates the country on either side, an innumerable quantity of aquatics leave its course for the West India islands on the north, and the valley of the Amazon on the south, the increased depth of the river, and the flooded state of the shores, depriving them of the usual supply of fish and insects. Upon the stream decreasing, and retiring within its bed, the birds return.
"The Lord is my light and my salvation; whom shall I fear? the Lord is the strength of my life; of whom shall I be afraid?"—Psalm xxvii.
1331. A comparison between the quadrupeds of the Old and New Worlds is in every point strikingly in favour of the former. Not only has the western continent no animals of such giant bulk as those of the eastern, but no examples of such high organisation, such power and courage, as the African lion and the Asiatic tiger display. Buffon's remark must indeed be considerably modified, respecting the cowardice of the American feline race; for the jaguar of the woods about the Amazon, when attacked by man, will not hesitate to accept his challenge, will even become the assailant, nor shrink from an encounter against the greatest odds. The following passages from the writings of Humboldt show that this transatlantic animal is not to be despised:—
"The night was gloomy; the Devil's Wall and its denticulated rocks appeared from time to time at a distance, illuminated by the burning of the savannahs, or wrapped in ruddy smoke. At the spot where the bushes were the thickest, our horses were frightened by the yell of an animal that seemed to follow us closely. It was a large jaguar, that had roamed for three years among these mountains. He had constantly escaped the pursuit of the boldest hunters, and had carried off horses and mules from the midst of enclosures; but, having no want of food, had not yet attacked men. The negro who conducted us uttered wild cries. He thought he should frighten the jaguar; but these means were of course without effect. The jaguar, like the wolf of Europe, follows travellers even when he will not attack them; the wolf in the open fields and in unsheltered places, the jaguar skirting the road, and appearing only at intervals between the bushes."
The same illustrious observer also remarks,—
"Near the Joval, nature assumes an awful and savage aspect. We there saw the largest jaguar we had ever met with. The natives themselves were astonished at its prodigious length, which surpassed that of all the tigers of India I had seen in the collections of Europe."
Still these were extraordinary specimens of the race, and leave the fact undoubted, that the most formidable of the western Feræ has no pretensions to an equality with his congener, the tyrant of the jungles of Bengal.
1332. In vain also we look among the tribes of America for a rival in outward appearance to the giraffe, so remarkable for its height, its swan-like neck, gentle habits, and soft expressive eye; while of the animals most serviceable to mankind—the horse, the ox, the ass, the goat, and the hog—not a living example of either was known there before its occupancy by the Europeans. But, however inferior the animal race of the New may be as compared to those of the Old world, the balance between the two appears to have been pretty equal in remote ages; geological discovery has disproved the assertion of Buffon, that the creative force in America in relation to quadrupeds never possessed great vigour, and has established the fact, that it is only the more recent specimens of its energy that are upon an inferior scale. The relics of the unwieldly magatherium, of the gigantic sloth, and armadillo-like animals, discovered in great abundance imbedded in its soil, prove that at a former period it swarmed with monsters of equal bulk with those that now roam in the midst of Africa and Asia. The estuary deposit that forms the plains westward of Buenos Ayres, and covers the gigantic rocks of the Bando Oriental, appears to be the grave of extinct gigantic quadrupeds.
"But wild beasts of the desert shall lie there; and their houses shall be full of doleful creatures; and owls shall dwell there, and satyrs shall dance there."—Isaiah xiv.
1333. There are various animals which are very widely dispersed, enduring the extremes of tropical heat and of polar cold, which are either in a wild condition or in a state of domestication. Wild races, considered to be varieties of the domestic dog, occur in India, Sumatra, Australia, Beloochistan, Natolia, Nubia, various parts of Africa, and both the Americas; while in subjection to man, the dog is his faithful companion, and has followed his steps into every diversity of climate and of situation to which he has wandered. The north temperate zone of the Old Continent appears to be the native region of the ox, which passes in Lapland within the arctic circle, and has been spread over South America since its first introduction by the Spaniards. The horse, originally an inhabitant of the temperate parts of the Old World, has shared in a similar dispersion, and now exists in the high latitude of Iceland, in the desolate regions of Patagonia, and roams wild in immense herds over the Llanos of the Orinoco, leading a painful and restless life in the burning climate of the tropics. Humboldt draws a striking picture of the sufferings of these gifts of the Old World to the New, returned to a savage state in their western location.
"In the rainy season, the horses that wander in the savannah, and have not time to reach the rising grounds of the Llanos, perish by hundreds amidst the overflowings of the rivers. The mares are seen, followed by their colts, swimming, during a part of the day, to feed upon grass, the tops of which alone wave above the waters. In this state they are pursued by the crocodiles; and it is by no means uncommon to find the prints of the teeth of these carnivorous reptiles on their thighs. Pressed alternately by excess of drought and of humidity, they sometimes seek a pool, in the midst of a bare and dusty soil, to quench their thirst; and at other times flee from water and the overflowing rivers, as menaced by an enemy that encounters them in every direction. Harassed during the day by gad-flies and mosquitoes, the horses, mules, and cows find themselves attacked at night by enormous bats, that fasten on their backs, and cause wounds which become dangerous, because they are filled with acaridæ and other hurtful insects. In the time of great drought, the mules gnaw even the thorny melocactus (melon-thistle), in order to drink its cooling juice, and draw it forth as from a vegetable fountain. During the great inundations, these same animals lead an amphibious life, surrounded by crocodiles water-serpents, and manatees. Yet, such are the immutable laws of nature, their races are preserved in the struggle with the elements, and amid so many sufferings and dangers. When the waters retire, and the rivers return into their beds, the Savannah is spread over with a fine odoriferous grass; and the animals of old Europe and Upper Asia seem to enjoy, as in their native climates the renewed vegetation of spring."
1334. The first colonists of La Plata landed with seventy-two horses, in the year 1535, when, owing to a temporary desertion of the colony, the animals ran wild; and in 1580, only forty-five years afterwards, it had reached the Straits of Magellan. The ass has a more restricted range than the horse, not being capable of enduring so great a degree of cold, though usually far from being considered a delicate animal. To the warmer parts of the temperate zone, between the 20th and the 40th parallels of latitude, the ass seems best adapted, not propagating much beyond the 60th, and only occurring in a state of degeneration beyond the 52nd. The sheep and goat tribe are widely spread, equally supporting the extremes of temperature. According to Zimmerman, the Argali or Mouflon, the original race of sheep, still exists on all the great mountains of the two continents; and the Capricorn and Ibex, the ancestors of the common goat inhabit the high European elevations. From the 64th degree of north latitude the hog is met with all over the old continent, and also in the islands of the Indian Ocean, peopled by the Malay race; and since its introduction into the New World, it has diffused itself over it, from the 50th parallel north as far as Patagonia. Originally the cat was not known in America, nor in any part of Oceanica; but it has now spread into almost every country of the globe. Among animals entirely wild, the most extensively diffused, are the fox, hare, squirrel, and ermine; but the species are different in every region of the world; nor is there perhaps one example to be found of a species perfectly identical naturally existing in distant localities of the earth.
"His going forth is from the end of the heaven, and his circuit unto the ends of it; and there is nothing hid from the heat thereof."—Psalm xix.
Respecting the internal constitution and heat of the earth, differences of opinion, and some very wild speculation have existed. We find in Humboldt's "Cosmos" the following remarks:—
1335. "It has been computed at what depths liquid and even gaseous substances, from the pressure of their own superimposed strata, would attain a density exceeding that of platinum, or of iridium; and in order to bring the actual degree of ellipticity, which was known within very narrow limits, into harmony with the hypothesis of the infinite compressibility of matter, Leslie conceived the interior of the Earth to be a hollow sphere, filled with "an imponderable fluid of enormous expansive force." Such rash and arbitrary conjectures have given rise, in wholly unscientific circles, to still more fantastic notions. The hollow sphere has been peopled with plants and animals, on which two small subterranean revolving planets, Pluto and Proserpine, were supposed to shed a mild light. A constantly uniform temperature is supposed to prevail in these inner regions, and the air being rendered self-luminous by compression, might well render the planets of this lower world unnecessary. Near the north pole, in 82 deg. of latitude, an enormous opening is imagined, from which the polar light visible in Aurora streams forth, and by which a descent into the hollow sphere may be made. Sir Humphry Davy and myself were repeatedly and publicly invited by Captain Symmes to undertake this subterranean expedition; so powerful is the morbid inclination of men to fill unseen spaces with shapes of wonder, regardless of the counter-evidence of well-established facts, or universally recognised natural laws. Even the celebrated Halley, at the end of the 17th century, hollowed out the earth in his magnetic speculations; a freely rotating subterranean nucleus was supposed to occasion, by its varying positions, the diurnal and annual changes of the magnetic declination. It has been attempted in our own day, in tedious earnest, to invest with a scientific garb that which, in the pages of the ingenious Holberg, was an amusing fiction."
The following are among the speculations which Humboldt thus severely but justly condemns:—
"The increase of temperature observed is about 1 deg. Fahr. for every fifteen yards of descent. In all probability, however, the increase will be found to be in a geometrical progression as investigation is extended; in which case the present crust will be found to be much thinner than we have calculated it to be. And should this be found to be correct, the igneous theory will become a subject of much more importance, in a geological point of view, than we are at present disposed to consider it. Taking, then, as correct, the present observed rate of increase, the temperature would be as follows:
Water will boil at the depth of 2,430 yards.
Lead melts at the depth of 8,400 yards.
There is red heat at the depth of 7 miles.
Gold melts at 21 miles.
Cast iron at 74 miles.
Soft iron at 97 miles.
And at the depth of 100 miles there is a temperature equal to the greatest artificial heat yet observed; a temperature capable of fusing platina, porcelain, and indeed every refractory substance we are acquainted with. These temperatures are calculated from Guyton Morveau's corrected scale of Wedgwood's pyrometer; and if we adopt them, we find that the earth is fluid at the depth of 100 miles from the surface, and that even in its present state very little more than the soil on which we tread is fit for the habitation of organised beings."
"He hath filled the hungry with good things; and the rich he hath sent empty away."—Luke i.
The above is to be found in Mr. Timbs's "Things not Generally Known," a little book which professes to set people right upon points on which they are in error!
Upon this subject Mr. Hunt, in his "Poetry of Science," says:—
1336. "A question of great interest, in a scientific point of view, is the temperature of the centre of the earth. We are, of course, without the means of solving this problem; but we advance a little way onwards in the inquiry by a careful examination of subterranean temperature at such depths as the enterprise of man enables us to reach. These researches show us, that where the mean temperature of the climate is 50 deg., the temperature of the rock at 59 fathoms from the surface is 60 deg.; at 132 fathoms it is 70 deg; at 239 fathoms it is 80 deg.; being an increase of 10 deg. at 59 fathoms deep, or 1 deg. in 35.4 feet; of 10 deg. more at 73 fathoms deeper, or 1 deg. in 43.8 feet; and of 10 deg. more at 114 fathoms still deeper, or 1 deg. in 64.2 feet.
Although this would indicate an increase to a certain depth of about one degree in every fifty feet, yet it would appear that the rate of increase diminishes with the depth. It appears therefore probable, that the heat of the earth, so far as man can examine it, is due to the absorption of the solar rays by the surface. The evidences of intense igneous action at a great depth cannot be denied, but the doctrine of a cooling mass, and of the existence of an incandescent mass, at the earth's centre, remains but one of those guesses which active minds delight in."
Upon the subject of hunger and thirst, by which living creatures are prompted to feast upon the bounties of nature, Sir Charles Bell says, in "Appendix to Paley's Natural Theology:"—
1337. "Hunger is defined to be a peculiar sensation experienced in the stomach from a deficiency of food. Such a definition does not greatly differ from the notions of those who referred the sense of hunger to the mechanical action of the surfaces of the stomach upon each other, or to a threatening of chemical action of the gastric juice on the stomach itself. But an empty stomach does not cause hunger. On the contrary, the time when the meal has passed the stomach is the best suited for exercise, and when there is the greatest alacrity of spirits. The beast of prey feeds at long intervals; the snake and other cold-blooded animals take food after intervals of days or weeks. A horse, on the contrary, is always feeding. His stomach, at most, contains about four gallons, yet throw before him a truss of tares or lucerne, and he will eat continually. The emptying of the stomach cannot, therefore, be the cause of hunger.
"The natural appetite is a sensation related to the general condition of the system, and not simply referable to the state of the stomach; neither to its action, nor its emptiness, nor the acidity of its contents; nor in a starved creature will a full stomach satisfy the desire of food. Under the same impulse which makes us swallow, the ruminating animal draws the morsel from its own stomach.
1338. "Hunger is well illustrated by thirst. Suppose we take the definition of thirst—that it is a sense of dryness and constriction in the back part of the mouth and fauces; the moistening of these parts will not allay thirst after much fatigue or during fever. In making a long speech, if a man's mouth is parched, and the dryness is merely from speaking, it will be relieved by moistening, but if it comes from the feverish anxiety and excitement attending a public exhibition, his thirst will not be so removed. The question, as it regards thirst, was brought to a demonstration by the following circumstance. A man having a wound low down in his throat, was tortured with thirst; but no quantity of fluid passing through his mouth and gullet, and escaping by the wound, was found in any degree to quench his thirst."
"Let us hear the conclusion of the whole matter; Fear God, and keep his commandments: for this is the whole duty of man."—Ecclesiastes xii.
"Thirst, then, like hunger, has relation to the general condition of the animal system—to the necessity for fluid in the circulation. For this reason, a man dying from loss of blood suffers under intolerable thirst. In both thirst and hunger, the supply is obtained through the gratification of an appetite; and as to these appetites, it will be acknowledged that the pleasures resulting from them far exceed the pains. They gently solicit for the wants of the body; they are the perpetual motive and spring to action."
Our task draws near to a conclusion; and we hope that those who have followed our teachings will thirst after further knowledge; that they will henceforward regard the great Book of Nature as the work of an Almighty Hand, and endeavour to find, for everything that Nature does, the Reason Why.
A high perception of the wisdom of the Divine Being, must necessarily be the result of an intelligent contemplation of the Divine works. To the ignorant, the name of God is an unmeaning word; it may inspire fear, but it does not develope love. To the dark mind of the untaught man, God is no more than one of those mysterious existences that awe the superstitious, and deter the wicked. There is no grafting of the soul of the man upon the eternal love. But knowledge brings man into communion with that Almighty wisdom which is the fountain of all truth and happiness. To the enlightened man, God is the sun of all goodness, around whom the attributes of Power, Wisdom, and Love, radiate and fill the universe. As man's physical eye cannot withstand the light of the sun, neither can man's spiritual eye see the whole glory of God. But as we can rejoice in the sunshine, and interpret the mission of the sunbeam, so can we find happiness in the Divine presence, and gather wisdom by the contemplation of the Creator's works.
Nature is a great teacher. What a lesson may be gathered from the germination of a seed; how uniformly the germs obey their destiny. However carelessly a seed may be set in the ground, the germ which forms the root, and that which is the architect of the stem, will seek their way—the one to light, the other to darkness—to fulfil their duty. The obstruction of granite rocks, cannot force the rootlet upward, nor drive the leaflet down. They may kill the germs by exhausting their vital powers in an endeavour to find the proper elements; but no obstruction can make a single blade of grass do aught but strive to fulfil the end for which it was created. Would that man were equally true to the purpose of his existence, and suffered neither the rocks of selfishness, nor the false light of temptation, to force or allure him from duty to his God.
THE END.
A BOOK OF UNIVERSAL KNOWLEDGE.
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THE TITLE OF THIS WONDERFUL BOOK, IS AS FOLLOWS:
INQUIRE WITHIN
FOR ANY THING YOU WISH TO KNOW; OR
OVER 3,700 FACTS FOR THE PEOPLE.
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LIVE AND LEARN;
A GUIDE FOR ALL WHO WISH TO SPEAK AND WRITE CORRECTLY:
particularly intended as a Book of Reference for the Solution of Difficulties connected with Grammar, Composition, Punctuation, &c., with Explanations of Latin and French words and Phrases of frequent occurrence in Newspapers, Reviews, Periodicals, and Books in general containing Examples of
ONE THOUSAND MISTAKES
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"Live and Learn" is a most useful book, designed as a Guide to Grammar, Composition, and Punctuation. So few people speak or write really good grammar, and fewer still punctuate decently, that a book that informs them how to do so—and not only that indicates their faults, but shows them how they are to be corrected—cannot fail to be popular; there is not a person indeed, who might not learn something from it.
No work heretofore written on this subject contains one half the really useful information that the present does. It should be in the hand of every man, woman and child in the country, and is alike invaluable to the Scholar, the Merchant, the Farmer, and the Artizan.
There are hundreds of persons engaged in professional and commercial pursuits, who are sensible of their deficiencies on many points connected with the grammar of their own tongue, and who, by self-tuition, are anxious to correct such deficiencies, and to acquire the means of speaking and writing, if not with elegance at least with a due regard to grammatical accuracy, to whom this little work is "indispensible." As a book of reference, "Live and Learn" will settle many disputes. It ought to be on every table, and be particularly recommended to the young, before habit makes common blunders uncommon hard to cure.
OPINIONS OF THE PRESS.
"Live and Learn" is an excellent book. To show our appreciation of its merits we have had it cased in leather, and have made a pocket companion of it. We look upon it as really indispensible. We advise our readers to imitate our example—procure the book and sell it not for any price—Educational Gazette.
Such a book as this has long been wanted by those who entertain the wish alluded to in the title. It is suitable for all classes. We have attentively conned its pages, and can recommend it as one of the best works of reference for the young student, or even the ripe scholar, and as deserving to be generally consulted. The work is altogether useful and indispensible.—New York Tribune.
This book, particularly intended as a work of reference for the solution of difficulties connected with grammar, composition and punctuation, etc., etc., will be found useful by those who have not received a sound elementary education and who nevertheless move in position.—Daily Times.
This capital work not only gives examples of over 1000 mistakes, but it gives rules for their correction so clear, so terse, and at once so simple that the most ordinary mind cannot fail to comprehend their meaning. This is one of the chief beauties of "Live and Learn," for what is the use of pointing out a grammatical error without giving a key to its correction? There has been several catchpenny works on this subject lately issued. They tell the reader that mistakes exist, but give no rule for their avoidance. If you want a really good work, buy "Live and Learn."
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EVERY MAN A MAGICIAN.
THE MAGICIAN'S OWN BOOK;
OR,
The Whole Art of Conjuring.
Being a Complete Hand-Book of Parlor Magic, containing over One Thousand Optical, Chemical, Mechanical, Magnetical, and Magical Experiments, Amusing Transmutations, Astonishing Sleights and Subtleties, Celebrated Card Deceptions, Ingenious Tricks with Numbers, Curious and Entertaining Puzzles—Together with all the most Noted Tricks of Modern Performers. The whole Illustrated with
OVER 500 WOOD CUTS,
And intended as a source of amusement for
ONE THOUSAND AND ONE EVENINGS.
12mo., cloth, 400 pages; gilt side and back stamp. Price, ONE DOLLAR, sent free of postage.
Here is a book for the long winter evenings, and one that will make all merry and happy. It contains over a THOUSAND TRICKS, of every description, and they are all explained so clear and explicitly that any person can comprehend and perform them with ease. It also contains numerous CURIOUS PUZZLES, with patterns showing how they are done, any one of which will afford amusement enough for a whole evening. There is, also, the best collection of wonderful CARD DECEPTIONS ever yet published, any one of which is worth more than double the price of the book. This work also contains a splendid collection of CURIOUS TRICKS WITH NUMBERS, and embraces several hundred tricks never before in print. It is no catchpenny affair, but a standard work, containing every variety of Experiment in Conjuring, Cards, Legerdemain, Transmutations, the Magic of Chemistry, the Magic of Mechanics, the Magic of Pneumatics, the Magic of Numbers, the Magic of Art, the Magic of Strength, the Magic of Magnetism, the Magic of Secret Writing, Miscellaneous Curious Tricks and Fancies, &c. This book is beautifully bound in fine cloth, with gilt side and back stamp, and is illustrated with
OVER 500 WOOD ENGRAVINGS,
Besides a Tinted Title Page and Frontispiece. Price, ONE DOLLAR, and sent to any address, free of postage.
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THE FOUNTAIN OF ALL KNOWLEDGE.
THE REASON WHY:
A CAREFUL COLLECTION OF
Some Thousands of Reasons for Things which, though Generally Known, are Imperfectly Understood.
A BOOK OF CONDENSED SCIENTIFIC KNOWLEDGE FOR THE MILLION.
BY THE AUTHOR OF "INQUIRE WITHIN."
This is a goodly sized volume of 356 pages, comprising a sort of Encyclopedia of Scientific Information of all kinds. It is arranged with an Alphabetical Index, in referring to which you can solve almost any problem in Natural Philosophy or Learned Science that may come up. It is a book that will give you the cream of the information that a long course of practical experiments and profound study has imparted to the savants and philosophers of this progressive age. It contains a collection and solution of Thirteen Hundred & Thirty-Two Facts in Science & Philosophy, some of which, on their first discovery, puzzled the most learned and apt scholars.
It is useless to go into details of this excellent work. Suffice it to say, that it treats on every imaginable subject pertaining to Causes and Effects, and must necessarily be invaluable to all persons who desire KNOWLEDGE, and whose means and position in life have prevented them from acquiring it by a regular and tedious course of Study.
We hesitate not to say, that any one who closely reads this volume will obtain as much real learning in a few days as years of study and patient research would afford them in a regular course. In a word it makes you a learned and refined person with spending but very little money, time or trouble.
No pains have been spared by the Author to make this a popular book, in fact a book for the million, and some idea may be formed of its vast usefulness when we inform the reader that THE REASON WHY has an Index of Contents requiring Forty Columns of Fine Type.
No person who desires to figure in refined and intelligent circles should delay purchasing a copy of this capital work, for it will furnish thousands of ideas and important topics of conversation, so that the most ignorant person by reading it will be posted up on all scientific subjects.
What Haydn's Dictionary of Dates is in regard to historical events, this wonderful book is in respect to scientific facts. The plan of the book and its execution, leave nothing to be desired. We can cordially recommend this work to all those inquirers, young and old, of both sexes, who are never satisfied until they know the "reason why."
The man who goes out into the world, or attempts to attend properly to his domestic duties, will find himself, however abundantly supplied with books or bullion, perpetually embarrassed for the want of small facts and small change. This volume supplies the Ready Coin of Conversation.
In the shape of SCIENCE FOR THE MILLION, and makes even the neglected in early studies feel quite at home upon every topic likely to be discussed within the ordinary range of the social circle. It imparts Practical Information on the Subject of Practical Facts.
It may be denominated, Science made easy, or a world of useful every-day learning condensed into a volume for your pocket!
THE REASON WHY
Is a handsome 12mo. volume of 356 pages, printed on fine paper, bound in cloth, gilt, and embellished with a large number of Wood Cuts, illustrating the various subjects treated of.
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SAM SLICK'S NEW WORK.
"Buy it, and if you don't laugh, then there is no laugh in you."—OHIO STATESMAN.
JUST PUBLISHED,
NATURE AND HUMAN NATURE
A Sequel to "Wise Saws; or, Sam Slick in Search of a Wife."
BY JUDGE HALIBURTON,
Author of "Sam Slick, the Clockmaker," "Old Judge," &c., &c.
NEATLY BOUND IN MUSLIN, 75 CENTS; IN PAPER, 50 CENTS.
CONTENTS.
- A Surprise.
- Clippers and Steamers.
- Unlocking a Woman's Heart.
- A Critter with a Thousand Virtues and but One Vice.
- A New Way to Learn Gaelic.
- The Wounds of the Heart.
- Fiddling and Dancing, and Serving the Devil.
- Stitching a Button-Hole.
- The Plural of Moore.
- A Day on the Lakes.
- The Betrothal.
- A Foggy Night.
- Female Colleges.
- Gipseying.
- The World before the Flood.
- Lost at Sea.
- Holding up the Mirror.
- The Bundle of Sticks.
- Town and Country.
- The Honeymoon.
- A Dish of Clams.
- The Devil's Hole; or, Fish and Flesh.
- The Cucumber Lake.
- The Recall.
NOTICES OF THE PRESS.
"The writings of Judge Haliburton have long been regarded as the production of the finest humorist that has ever attempted the delineation of Yankee character, and the entertaining work before us shows that he has lost none of his original wit and humor. It will be difficult to find a volume so full of fun and good sense as this, which chronicles the last experiences of Sam Slick."—Commercial Advertiser.
"Since Sam Slick's first work he has written nothing so fresh, racy, and genuinely humorous as this. Every line of it tells, some way or other—instructively, satirically, jocosely or wittily."—London Observer.
"We sincerely pity the man who cannot find in it the materials for the loosening of several of his coffin nails. It is full of oddity and fun, and must sell like new tomatoes."—Buffalo Express.
Published by DICK & FITZGERALD, 18 Ann St., N. Y.
And for sale by all the principal Booksellers.
☞ Persons forwarding the price by mail will receive the Work FREE OF POSTAGE. ☜
DICK & CO.'S LIST OF PUBLICATIONS.
A Book for Housekeepers.
THE AMERICAN HOME COOK-BOOK.
Containing several hundred
EXCELLENT RECIPES.
The whole based on many years' experience of an American Housewife. Illustrated with engravings. Price 25 cents.
All the Recipes in this book are written from actual experiments in Cooking. There are no copying from theoretical cooking recipes. They are intended for American families, and may be depended upon as good and practicable. The authoress is a lady who understands how cooking ought to be done, and has here given her experience. It is a book of 128 pages, and is CHEAP at 25 cents. We expect to sell a very large number at this low price.
Works for the Ladies.
THE LADIES' GUIDE TO BEAUTY.
A COMPANION FOR THE TOILET.
Paper ... 25 cts.
Cloth ... 37½ "
Containing Practical Advice on Improving the Complexion, the Hair, the Hands, the Form, the Teeth, the Eyes, the Feet, the Features, so as to insure the highest degree of perfection of which they are susceptible. And also upwards of One Hundred Recipes for various Cosmetics, Oils, Pomades, etc., etc., being the result of a combination of Practical and Scientific Skill. By Sir James Clark, Private Physician to Queen Victoria. Revised and edited by an American Physician and Chemist.
Price 25 cents, and we send it free of postage.
LADIES' GUIDE TO CROCHET.
BY MRS. ANN S. STEVENS.
Copiously illustrated with original and very choice Designs in Crochet, etc., printed in colors, separate from the letter-press, on tinted paper. Also with numerous wood-cuts printed with the letter-press, explanatory of terms, etc. Oblong, pp. 117, beautifully bound in extra cloth, gilt. Price 75 cents.
This in by far the best work on the subject of Crochet yet published. There are plenty of other books containing Crochet patterns, but the difficulty is, they do not have the necessary instructions how to work them, and are, therefore, useless. This work, however, supplies this much felt and glaring deficiency, and has the terms in Crochet so clearly explained that any Crochet pattern, however difficult, may be worked with ease.
Copies of the above mailed to any address in the United States free of postage.
Books by Celebrated Authors.
WHICH—THE RIGHT OR THE LEFT?
A Religions Novel. Royal 12mo., cloth. 534 pages. Price $1 25.
This work has received favorable notice from the entire secular as well as the religious press. The main design of the author in the illustration of the fact that success in business may easily consort with fervid piety and the strictest honesty on the part of those engaged in it. The story is that of a young man, the son of a country pastor, who goes as an assistant into a dry goods store, at New York; and not only maintains his religious principles amidst the allurements of the capital, but succeeds in drawing within their happy influence a number of the clerks and other assistants, who at first scoffed at his "rural piety," as they termed it, but were at length led by him to abandon the frivolities which had formed their former delight, and devote themselves to religious exercises and the visitation of the sick and poor. His influence reached even a higher circle; and the author gives us some lively sketches of the insipidity and heartlessness of fashionable life, whose unhappy devotees choose to live for society and self, rather than for Religion and their fellow-creatures.
⁂ The Publishers have in their possession, testimonials from over three hundred of the principal Clergymen in the United States and Canada, pronouncing this to be the best work that has been published for years, and in every instance they are the honest convictions formed after an actual perusal of the volume itself. This work has also received high laudation from almost every paper of character and standing in this country. Added to which it has been read by thousands, and has received universal commendation.
ESTELLE GRANT; OR, THE LOST WIFE.
Large 12mo., cloth. Price $1 00.
This is a book so thoroughly excellent, so exalted in its character, so full of exquisite pictures of society, and manifesting so much genius, skill, and knowledge of human nature, that no one can possibly read it without admitting it to be, in every way, a noble book. The story, too, is one of stirring interest; and it either sweeps you along with its powerful spell, or beguiles you with its tenderness, pathos, and geniality.
THE PILGRIMS OF WALSINGHAM.
A Romance of the Middle Ages, from the accomplished pen of Agnes Strickland.
Large 12mo., pp. 460. Price $1 00.
Truly a charming book! Full of the profoundest interest, yet not one improbable incident—not one prurient idea. You will sooner find spots upon the leaves of the silvery lily than an impure sentence in a book by this author.—Buffalo Courier.
NA MOTU; OR, REEF ROVINGS IN THE SOUTH SEAS.
A Narrative of Adventures in the Hawaiian, Georgian, and Society Islands, with original illustrations.
BY EDWARD T. PERKINS
12mo. Cloth. $1 00
Na Motu is the quaint title of a handsome volume of voyage and adventure in the South Seas. Mr. Perkins, the author, a schoolmate of Ike Marvel, has spent several years before the mast, and on the salt water in other capacities, and his style is characterized by a straightforward, honest nonchalance and idiomatic flavor, redolent of Old Ocean from stem to stern. His daguerreotype of nautical dialogues is only a little too perfect, occasionally, for good taste; a large portion of his experience being gained on a whaling ship.—New York Church Jour.
SAM SLICK'S YANKEE COURTSHIP.
RECENTLY PUBLISHED,
WISE SAWS;
OR,
SAM SLICK IN SEARCH OF A WIFE.
By the Author of "Sam Slick In England," "Nature and Human Nature," "Sam Slick's Sayings and Doings," &c.
In One Elegant Volume, neatly bound in Muslin;
Price 75 Cts.—in Paper 50 Cts.
Extract from the Preface:
* * * * "Fun has no limits. It is like the human race and face; there is a family likeness among all the species, but they all differ. New combinations produce new varieties. A man who has an eye for fun sees it in everything. * * * There is a work called 'The Horse,' and another 'The Cow,' and 'The Dog,' and so on; why should'nt there be one on 'The Galls?' They are about the most difficult to choose and to manage of any created critter, and yet there aint any dependable directions about pickin' and choosin' of them. Is it any wonder then so many fellows get taken in when they go for to swap hearts with them? Besides; any one can find a gentleman that keeps a livery stable to get him a horse to order, but who can say, 'This is the Gall for your money!'"
CONTENTS.
- Introductory Letter,
- Chat with the President,
- Stealing a Speech,
- Everything in General, and Nothing in Particular,
- The black Hawk: or Life in a Fore-and-After,
- Old Blowhard,
- The Widow's Son,
- The Language of Mackerel,
- The Best-natured Man in the World,
- The Bait-Box,
- The Water-Glass; or a Day-Dream of Life,
- Old Sarsaparilla Pills,
- Our Colonies and Sailors,
- The House that Hope Built,
- The House without Hope,
- An Old Friend with a New Face,
- Chat in a Calm,
- The Sable Island Ghost,
- The Witch of Eskisoony,
- Jericho beyond Jordan,
- Three Truths for One Lie,
- Aunt Thankful & her Room,
- A Single Idea,
- An Excellent Plan of Reform,
- Goose Van Dam,
- A Hot Day,
- A Pic-Nic at La Haire,
- A Narrow Escape.
Published by DICK & FITZGERALD, 18 Ann St., N. Y.
And for sale by all the principal Booksellers.
THE ARTIST'S BRIDE;
OR, THE PAWNBROKER'S HEIR.
A Novel, by EMERSON BENNET.
12mo. Cloth,—420 pages,—Price 1 00.
"We have perused this work with some attention, and do not hesitate to pronounce it one of the very best productions of the talented author. There is not a page that does not glow with thrilling and interesting incident, and will well repay the reader for the time occupied in perusing it. The characters are most admirably drawn, and are perfectly natural throughout. We have derived so much gratification from the perusal of this charming novel, that we are anxious to make our readers share it with us: and, at the same time, to recommend it to be read by all persons who are fond of romantic adventures. Mr. Bennett is a spirited and vigorous writer, and his works deserve to be generally read; not only because they are well written, but that they are, in most part, taken from events connected with the history of our own country, from which much valuable information is derived, and should, therefore, have a double claim upon our preference, over those works where the incidents are gleaned from the romantic legends of old castles and foreign climes."—Louisville Journal.
DICK TARLETON;
OR,
THE LAST OF HIS RACE.
Containing 112 very large octavo pages. Price 25 cts. and the book sent free of postage. This well written work has been pronounced by good judges to be the best of Mr. Smith's production. This is saying a great deal, considering that gentleman is the author of "Minnie Grey," and "Woman and her Master,"—works which have become famous with novel readers.
CYRILLA;
A ROMANCE.
BY THE AUTHOR OF THE INITIALS.
Large Octavo.—Price 50c.
Every person who has read that charming novel, "The Initials," should purchase a copy of "Cyrilla." It is one of the best novels that has been published in the past ten years. There is, probably no work of fiction now before the public that surpasses it for power, pathos, depth of plot, delineation of character and brilliancy of sentiment. It forcibly shows that "Many who have perished have erred and sinned for woman."
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New Works by Miss E. Marryatt.
(DAUGHTER OF CAPTAIN MARRYATT.)
HENRY LYLE; OR LIFE AND EXISTENCE.
12mo. Cloth, Price $1 00.
TEMPER; A TALE.
12mo. Cloth, Price $1 00.
The above novels, by the talented daughter of the late Captain Marryatt, were written in compliance with the wishes of her father, expressed a short time previous to his death; and the fair authoress alludes to this circumstance by way of apology, in the preface to "Temper." We predict for them a wide spread popularity. They are original in style, truly moral and religious in tone, and are calculated to accomplish much good, as the author aims some telling blows at the tendency of the present generation towards Infidelity, and other modern evils.
Works by the Author of "Zaidee."
ADAM GRAEME OF MOSSGRAY.
12mo. Cloth. Price $1 00.
The characters are painted in bold relief, and seem to live, move and speak before you. Not one is overdrawn, and yet each comes up to the popular standard, in point of interest, individualization, and spirit. The tale is, indeed, "sad, high and working; full of state and woe;" but it is pleasant enough for all that, and the sober, truthful earnestness with which it is related, will at once communicate itself to the mind of the most fastidious and hypercritical peruser of modern volumes.
MAGDALEN HEPBURN;
A Story of the Scottish Reformation.
12mo. Cloth, Price $1 00.
This charming novel, by the author of "Zaidee," will be welcomed by all who have had the pleasure of reading the former production. The quaint originality, the healthy and cheerful religious tone, and charming simplicity and good sense of this volume, will render it a general and permanent favorite. A work which will be read as long as any volume of our time. We know of no fiction, in fact, that we would sooner recommend; for, while it will fascinate all who merely read for amusement, it will delight as well as improve those who seek for something even in a novel. It is fascinating from beginning to ending, and no reader will lay it down, after perusal, without wishing the author had extended its pages.
A REPLY TO "DRED," AND "UNCLE TOM."
TIT FOR TAT;
A NOVEL,
BY A LADY OF NEW ORLEANS.
12mo. Cloth, Price $1. Sent free of postage.
This the title of a most wonderful book, written by a lady of New Orleans, and issued from the press for the perusal of all persons whose minds have been poisoned by the pernicious exaggerations of American life and Negro Slavery to be found in "Uncle Tom's Cabin" and "Dred." The lady of New Orleans has done her work manfully. The book shows clearly that those who cry out against Negro Slavery, and utter the rankest falsehoods about that institution, are the supporters and proprietors of a system of white slavery more cruel and debasing in its character and operations than the most skilful romancist could imagine. All this is shown in a Tale abounding with spirited and dramatic scenes and incidents. "TIT FOR TAT" embraces forty chapters of astonishing interest. MILLIONS of copies of this work should be circulated.
OPINIONS OF THE PRESS.
"It recounts, in a forcible manner, the evils of the English social system.... We only wish it furnished any sufficient apology for our shortcomings."—Commercial, Buffalo.
"One of the must powerfully written novels of the day."—Springfield Republican.
"It is a poem in all its parts; fervid, womanly and eloquent."—Galveston News.
"She shows clearly that those who cry out against Negro Slavery are the supporters of a system of white Slavery, most cruel and depraved."—Savannah News.
This is "carrying the war into Africa" with a vengeance. It is more than "a Roland for an Oliver." It is more caustic than even "Change for Dickens' American Notes. By a lady." "Dred, a Tale of the Dismal Swamp," the offspring of foreign influence; British influence; subsidising and Anglicising the Yankee pen of Harriet Beecher Stowe, is answered most effectually in a tale of white slavery, far more dismal than all the caricatures that have ever been painted of Negro servitude in the South. Our bane and antidote are both before us. "Tit for Tat" is confined to England and the English, and is, therefore, a more direct and appropriate reply to the Duchess of Sutherland's minion. The bold, startling pictures are drawn from real life, and their darkest shadows do not exaggerate the depths of degradation and misery into which the fairest specimens of God's handiwork are plunged; white men capable of appreciating misery in its highest forms, and of enjoying all its benefits and refinements. And all the suffering and woe depicted by the author with masculine vigor are the direct results of the cruel oppression of the aristocracy, to whom Mrs. Stowe plays the flunkey, flattering in their vices, the tyrants who wallow in luxury upon the toil and blood of the people.—New York Citizen.
Copies of the above books sent per mail free of postage. Send cash orders to
DICK & FITZGERALD.
No. 18 Ann Street, New York.