PART XI.
FORMULA FOR THE LESSON ON THE NERVOUS SYSTEM.
1. My brain is a soft gray-and-white mass resembling marrow.
2. It is placed in a bony box called the skull; it is covered and held together by three coats or membranes.
3. The outer membrane is thick and firm; it strengthens and supports the brain.
4. The middle membrane is thick, and somewhat like a spider's web in appearance.
5. The inner membrane is a network of blood-vessels.
6. From the brain, white or reddish gray pulpy cords, called nerves, pass to all parts of the body. These nerves are of two kinds: nerves of feeling, and nerves of motion.
7. If I prick my finger, a nerve of feeling carries the message to my brain; if I wish to move my finger, a nerve of motion causes my finger to obey my will.
8. Twelve pairs of nerves pass from the base of the brain: the first pair, called the nerves of smell, to my nose; the fourth pair, called the nerves of sight, to my eyes; the fifth pair, called the nerves of taste, to my mouth, tongue, and teeth. One pair pass to my face; another to my ears. The ninth, tenth, eleventh, and twelfth pairs to my tongue and parts of my throat and neck.[[3]]
9. The spinal cord is a bundle of nerves extending from the base of my brain, down through the whole length of my spine, or backbone. It is the largest nerve in my body.
10. From the spine, thirty-one pairs of nerves, called spinal nerves, pass to different parts of my body; some to the lungs, some to the heart, some to the stomach, some to the bones, and some to the muscles and skin.
11. If a nerve be destroyed it cannot carry messages to and from the brain. Before filling a tooth, the dentist sometimes destroys its nerve.
12. If a nerve be pressed upon too long it cannot perform its duty. If I press upon the nerve passing to my foot, I stop it from communicating with the brain; the foot loses its feeling, or, as I say, "is asleep."
13. If I drink alcoholic liquors, or snuff, smoke, or chew tobacco, my brain and nerves cannot do their work well; because alcohol and nicotine are very poisonous to the brain and nerves.
14. The brain must be supplied with good blood;
The brain must be used;
The brain must be rested;
I must drink wholesome drink, eat wholesome food, take enough exercise, and breathe pure air, that my brain may be supplied with pure blood;
I must study and think, that my brain may grow and be strong for work;
I must rest my brain when it is tired, either by changing my employment, or by going to sleep;
I must not poison my brain with alcohol or tobacco.
[3] NOTE.—A fuller description of the Nerves of the Brain: Twelve pairs of nerves pass from the base of the brain; the first pair, called the nerves of smell, to my nose; the second pair, called the nerves of sight, to my eyes; the third, fourth, and sixth pairs to the muscles of my eyes; the fifth pair to my forehead, eyes, nose, ears, tongue, teeth, and different parts of my face; the seventh pair to different parts of my face; the eighth pair, called the nerves of hearing, to the inner part of my ear; the ninth pair to my mouth, tongue, and throat; the twelfth pair to my tongue; the eleventh pair to my neck; the tenth pair to my neck, throat, lungs, stomach, and different parts of my body.
QUESTIONS ON THE FORMULA.
1. Describe the brain.
2. Where is the brain placed?
3. Describe the outer membrane of the brain.
4. Describe the middle membrane of the brain.
5. Describe the inner membrane of the brain.
6. Tell about the nerves.
7. Tell about the use of the two kinds of nerves.
8. Tell about the nerves which pass from the brain.
9. Tell about the spinal cord.
10. Tell about the nerves which pass from the spinal cord.
11. What happens if a nerve be destroyed?
12. What happens if a nerve be pressed upon too long?
13. What happens if you drink alcoholic liquors, or snuff, smoke, or chew tobacco?
14. What is necessary if you would have a healthy brain?
THE BRAIN AND ITS WORK.
The brain is egg-shaped, and of two parts, the large brain (cerebrum), and the little brain (cerebellum). These are composed of a white and gray substance, which in the large brain is so folded and wrinkled that it looks like the meat of an English walnut; in the little brain it is so arranged that it resembles a tree, and is called arbor vitæ, tree of life. The mind does its thinking through the large brain, and controls its muscles through the little brain.
A drunken man can not walk straight because alcohol has hurt the little brain; he can not think straight because it has poisoned the large brain.
C, the large brain (cerebrum). B, the small brain (cerebellum). S, a portion of the spinal cord.
QUESTIONS ON THE NERVOUS SYSTEM.
Where is your brain?—"In my skull."
What color is the brain?—"Gray and white."
What does the brain resemble?—"Marrow."
How is the brain protected?—"By three coats or membranes."
What may you name these membranes?—"The outer membrane, the middle membrane, and the inner membrane."
Describe the outer membrane. See Formula.
Describe the middle membrane. See Formula.
What are the nerves?—"White ashen-gray pulpy cords, which are found in the brain."
Where do they go from the brain?—"To every part of the body."
How many kinds of nerves have you?—"Two."
What names are given to the two kinds of nerves?—"Nerves of motion and nerves of feeling."
Which is the largest nerve in the body?—"The spinal cord."
Where is the spinal cord?—"It extends from the brain throughout the whole length of the backbone."
How may you describe the spinal cord?—"It is a bundle of nerves, etc." See Formula.
Where are the spinal nerves?—"They pass from the spinal cord to different parts of the trunk and limbs."
How many pairs of nerves pass from the base of the brain?—"Twelve."
Where do the first pair go?—"To the nose."
What are they called?—"The nerves of smell."
Where do the second pair go?—"To the eyes."
What are the second pair called?—"The nerves of sight."
Which move the muscles of the eyes?—"The third, fourth, and sixth pairs."
Where do the fifth pair go?—"To the forehead, eyes, nose, ears, tongue, teeth, and different parts of the face."
The seventh pair?—"To the different parts of the face."
The eighth pair?—"To the inner ear."
What are the eighth pair called?—"The nerves of hearing."
Where do the ninth pair go?—"To the mouth, tongue, and throat."
Where do the twelfth pair go?—"To the tongue."
Where do the eleventh pair go?—"To the neck."
Where do the tenth pair go?—"To the neck, throat, lungs, stomach, and different parts of the body."
What happens if a nerve be destroyed?—"It cannot carry messages to the brain."
What happens if a nerve be pressed upon too long?—"It cannot carry messages to the brain."
What is necessary if you would have a strong, healthy brain?—"My brain must be used; my brain must be rested; my brain must be supplied with pure blood."
How must you use your brain?—"In thinking and studying."
How may the brain be rested?—"By sleep."
In what other way may the brain be rested?—"By thinking of something different from that which made it tired."
What two brain-poisons have you learned about?—"Alcohol and tobacco."[[4]]
With what may you show the harm done by alcohol to the gray part of the brain?—"With alcohol and the white of an egg."
How could you show it with these?—"I would pour the alcohol upon the white of the egg."
What would then happen?—"The white of the egg would harden as if it had been boiled."
What is in the white of an egg?—"Water and albumen."
Where else may we find albumen?—"In some seeds, and in the gray part of the brain and the nerves."
What harm does alcohol do to the nerves?—"It takes away their moisture and hardens them."
What harm does this do to them?—"It paralyzes them, or makes them lose their power."
What happens when nerves are paralyzed?—"They lose their power over the muscles; they are unfit to carry messages to and from the brain."
What harm does alcohol do to the gray part of the brain?—"It hardens it, as it hardens the white of an egg."
What harm does this do to the brain?—"It paralyzes it, or makes it lose its power."
What then happens?—"It cannot properly do its work of thinking, and cannot control the nerves."
What disease is sometimes caused by this hardening of the brain by alcohol?—"Paralysis, which often ends in death."
What harm does alcohol do to the blood-vessels of the brain?—"It fills them with impure blood."
What disease is caused by the blood-vessels of the brain being filled with impure blood?—"Congestion of the brain, or apoplexy, which ends in death."
What else frequently happens to those who drink alcoholic liquors?—"They become crazy, or insane."
If you wish to have a strong, healthy brain, what should you do about these liquors?—
"Never put them into my mouth,
To steal away my brains."
Tell of what dreadful disease people die who are bitten by a mad dog.—"Of hydrophobia."
Of what dreadful disease do people sometimes die who are bitten by the serpent in alcoholic liquors?—"Of delirium tremens."
Which is the more dreadful, hydrophobia or delirium tremens?—"One is as dreadful as the other."
How can you be sure never to have delirium tremens?—"By drinking nothing which has alcohol in it."
Will a little beer or wine hurt you?—"Yes, it may make me love the taste of alcohol."
What harm is there in loving the taste of alcohol?—"I may love it so much as to become a drunkard."
Tell once more how you should treat alcoholic liquors.—"I should never drink a drop of them."