Foods; nutrition and digestion

by Susanna Cocroft

PURPOSES OF FOOD

The purposes of food are:

To supply the material of which the body is made.

To rebuild tissue, which is constantly being torn down and eliminated.

To produce heat, and to supply muscular and mental energy.

Let us discuss these purposes in above order.

Food Supply

By food supply is meant not only that the proper foods in kind and quantity be eaten, but that the body be in condition to digest, absorb, and assimilate the foods, and to eliminate the waste, otherwise the foods fail to supply the body needs. It is the nourishment which the body assimilates and appropriates to its needs which counts in food economy.

Of the fifteen to twenty substances contained in foods and comprising the body, the most abundant are oxygen, hydrogen, carbon, nitrogen, chlorin, sodium, potassium, magnesium, iron, calcium, phosphorus, and sulphur. All living matter, plant or animal, contains oxygen, hydrogen, carbon and nitrogen; the difference in the form and use of the matter is in the proportions of these elements.

Carbon combined with oxygen forms carbon dioxid. Hydrogen, nitrogen, and carbon dioxid form the air. Oxygen and hydrogen form water. Calcium, iron, magnesium, sodium, and potassium form the majority of rocks.

The substances contained in living organisms are the same as those in inorganic matter, only in different complexities as appropriated to each need. This difference in complexity of combinations of the same elements in a body is the physical difference between a living and a non-living plant or animal.

By far the most important change which the food must undergo to convert it from raw material into a state for conversion into body needs is the chemical change. While the body needs carbon, it cannot use coal; it needs nitrogen, yet it cannot appropriate it to rebuilding bone and muscle until, by chemical action with other elements within, it has been converted into complex substances called proteins; again, the chemical action of oxygen breaks down the proteins.

The muscles, ligaments, and labor-performing structures contain the largest amount of proteins; the fats and the carbohydrates contain the largest amount of carbonaceous compounds; the brain, the nerves, and the bones contain the largest portion of phosphorous compounds; yet, while the brain contains phosphorus, and the muscles nitrogen, the brain cannot be built up by eating elementary phosphorus, nor the muscles by pure nitrogen, but compounds rich in phosphorus or nitrogen may be utilized. It has been demonstrated by scientific investigation that no unorganized element is assimilated by the system and converted into its various structures.

The gluten of wheat is built up by the chemical union of nitrogen in the air and nitrogen in the soil with other substances. Plants are able to use the simple compounds of the earth, air, and soil, and, within their own cells, build them up into such complex substances as starch, sugar, protein, fat, and salt, which are appropriated by the animal kingdom for further growth and change.

In its conversion into tissue, heat, energy, and waste, the importance of the chemical exceeds the mechanical action, such as digestion, absorption, assimilation, and elimination; yet the chemical changes are aided by the mechanical.

Each individual should know, approximately, the chemical constituents and the proportion of these constituents in normal blood, because from the elements in the blood, the tissues are constructed. If certain elements be lacking, the foods containing these elements in largest proportions should be supplied until the blood no longer shows the deficiency. This is Nature’s method of correction.

Each meal, or each day’s food, may not contain just the amounts of protein or of fuel ingredients necessary for that day’s work and re-supply, but the body is continually storing material, and this reserve is constantly being drawn upon to provide any element which may be lacking in that day’s supply. Thus, an excess or a deficiency one day may be adjusted the next. Healthful nourishment requires that the balance, as a whole, be kept, and that a deficiency or over-supply be not continued for too long.

Many domestic animals take their food elements from air and water, as well as from the compounds which the plants have formed; while others make use of meat, a compound formed by another animal. The digestive forces of the animal has converted these elements into flesh, a compound easily assimilated by another.

The greater part of the muscles, nerves, and glands of the animal kingdom is protein. The skeleton is composed largely of deposited salts, while the elements which supply heat and keep up muscular activity are starches, fats, and sugars.

The proteins are appropriated by man from plants, but they are furnished to him in more easily digested form in lean meat and eggs, the lower animals having done much of the work of digestion, converting the proteins from plant life into more condensed form. On the other hand, by access to this concentrated form of easily digested protein, man is in danger of taking in too much of this condensed food, if he eats a large quantity of meat and eggs.

It must be apparent to every thoughtful person, since the nerves, muscles, and glands are composed largely of protein and the skeleton largely of salt, that, in order to furnish the body with the elements necessary for growth and repair, these elements must be provided, as also the substances producing the energy for the working body. Each individual should make a self-study to know how much re-supply is required to renew the daily waste.

About one-third of the food eaten goes to maintain the life of the body in doing its incessant work of repairing and rebuilding, the remaining two-thirds is the reserve for usefulness outside of itself.

One of the most remarkable, and the least understood of any of the assimilative and absorptive functions, is that any one part of the body has the power to appropriate from the foods the elements necessary for its own rebuilding, while these same elements pass through other organs untouched. The body has the power, also, to not only make use of the foods, but to use up the blood tissue itself. Just how this is done is also a mystery.

There is surely a great lesson in industry here, and one of the most profound studies in economics, physics, and chemistry.

Heat and Energy

The second use of foods, as mentioned before, is to create heat and energy for the work of the body. This includes the action of the heart; the movement of the lungs in breathing; the digestion, absorption, and assimilation of food elements; the tearing down and elimination of waste; and the muscular activity of body movements.

Just as any engine requires fuel, water, and air to create the force necessary to run the machinery, so does the human engine require fuel, air, and water. The fuel for the engine consists of coal, wood, or oil. As these are rapidly brought in combination with oxygen, combustion, or oxidation, takes place, liberating heat and setting the engine in motion. The amount of energy or force given off by an engine exactly equals the amount of latent energy provided in the fuel. Much of this energy is commercially lost, since much of the latent force in fuel is not fully liberated, some, not liberated, going off in the smoke, while some may remain in the cinders.

Just so in the body,—the amount of heat and energy given off from the body exactly equals the amount of latent energy released by material burned during oxidation. It is estimated that about one-sixth of the heat liberated evaporates through the skin, the lungs, and through the excreta, while five-sixths is required to maintain the body heat.

If the digestive forces are not working perfectly and if the food is not properly cooked, some of the food is not made perfectly soluble for absorption. But in normal conditions, if the food is supplied in proportion to the energy required, the heat and energy given off should exactly equal the latent heat and energy consumed in food.

It is to be noted, also, that no force within the body is lost. In the very process of the removal of waste, heat and energy are created, so that the parts no longer needed are utilized by the system, while they are being removed from it. Here is a lesson in economy of force.

As mentioned before, the fuel for the body consists of fats, starches, and sugar, which, in combination with oxygen, create force. The combination of oxygen with other elements in the body is known as oxidation. This oxidation liberates heat and at the same instant produces energy, either in muscle, gland or nerve. The muscular energy expresses itself in muscular motion, the glandular in chemical action, and the nervous in nervous energy. The nervous energy is closely allied to electrical force.

The starches come largely from cereals and root vegetables; the sugars largely from cane, from certain trees, and from vegetables, fruit, and milk; the fats come from vegetable oils, from animal fat, as fat, and some from milk and butter. Some fats are also formed from proteins.

From the above, it follows that the fuel value of food depends upon the amount of fats, starches, and sugars contained.

The exact process of the conversion of the potential energy latent in food into heat and energy is not known. It is partly released during the digestive process, as the elements of the food come into contact with the oxygen swallowed and with the digestive juices. This combustion gives to the digestive organs the necessary warmth for their effective work. Digestive juices will not flow freely when the body is cold. The heat liberated during the digestive process is necessary, also, to put the elements of the food into condition for absorption, a certain amount of heat being required for the chemical changes. This liberated energy is expressed, not alone in the chemical formation of the compounds, but in the peristaltic movements of the digestive organs.

A small portion of the heat of the body is gained from the sun or from artificial heat, but by far the greater part is generated within the body. If one is cold, the quickest way to get warm is to generate more heat within by “turning on the draught”, or, in other words, by breathing in more oxygen. So many people cover up the body with more clothing to reserve the body heat and forget to generate more heat by arousing the fires within. This is like covering up a dying fire to reserve the heat, instead of turning on the draught to create more combustion.

Nature provides for a reserve of heat and energy, above the immediate needs, by storing up a supply which is called into use whenever the daily supply is inadequate. Many hibernating animals store up sufficient fat in summer to provide heat for the entire winter. This fat would not last the winter, however, were the animal active. Many individuals store up excess of fat sufficient to last them for months, even though all fat building elements be omitted from the diet.

It must be remembered that anything which creates a greater activity of the tissues, such as muscular exercise, liberates a greater amount of heat. The reverse is also true;—a decrease in the amount of muscular movement means a decrease of heat liberated. During exercise, a large amount of fat, protein, and dextrose (sugar) are released by the movements and oxidized; the liberated heat is carried to all parts of the system and the temperature is raised. Mental work, for the same reason, tends to raise the body temperature, though to a much less degree. Food in the alimentary canal causes an activity in the glands of the digestive organs and also increases the temperature.

Of course, while digestion and mental and muscular activity are at their height, the body temperature is highest. These activities usually reach a maximum in the afternoon and the temperature is then highest, while, as a rule, it decreases from about six at night until four or five in the morning, when it is usually at its lowest ebb. This is a point of importance to physicians. Even five degrees above the average human temperature, if recorded about six at night, is not considered abnormal.

Anything which causes an increase in heat radiation, as perspiration, lowers the temperature, and the open pores of the skin are valuable aids in equalizing the body heat. A person who perspires freely does not suffer with heat, during excessive exercise, as does one whose pores are closed.

One ready means of regulating the body heat is the bath. If one takes a hot bath, the temperature is materially raised by the artificial heat, but there is a recompense in the increase of heat radiation from the skin. If one takes a cold bath, the immediate effect is cooling, but the activity set up within, to create a reaction, soon heats the body to a greater degree than before the bath. The best way to increase the evaporation and thus decrease the temperature of the body is with a tepid shower or a tepid sponge. The tepid water is not so extreme as to create a strong reaction and it will cause a marked decrease in temperature. Thus, for fever patients or for a warm day, the tepid shower or sponge is commended; for a cold day, or for the individual whose circulation is sluggish, the cold bath is desirable. Where the vitality is low, so that there is not sufficient reaction, the bath must be tempered.

Heat generation is also increased by solid foods that require more than normal activity on the part of the glands for digestion. For this reason the food for fever patients should be that most easily digested and should be reduced to the minimum to keep up the strength.

Diuretic foods and beverages, which increase the activity of the skin and the kidneys, also tend to lower the body temperature.

While the elements of the food are being oxidized, the latent (potential) energy released by the oxygen creates mental and physical force and keeps active the metabolic changing of food into tissues and cells, also the changing of cells and tissues into waste.

The young child’s blood circulates freely, his breathing is unrestricted, the waste of the system is fully burned up, potential energy is released, and the result is, he must be active. The effort of the teacher, or of those having the care of children should be, not to restrain the child, but rather to direct his activity in advantageous and effective use of his energy.

Scientists have a means of measuring the energy latent in food material, also the amount of heat given off in the oxidation of a given quantity of waste. The unit of measurement is the calorie,—the amount of heat which will raise one pound of water to four degrees Fahrenheit, or will lift one ton one and fifty-four hundredths.

Truly the body is a busy work-shop. Think of the billions upon billions of cells being formed and destroyed every instant in the liberation of heat and force! Think, also, of the necessity of perfect circulation to bring sufficient blood to the lungs, that it may gather the oxygen and carry it, without pausing for rest, to every tissue of the body! Even in sleep this stream continues incessantly.

There is also a great lesson here in the law of supply and demand;—when the body is at mental or muscular work, the potential energy liberated leaves through muscle or brain, as energy, and is expressed in the result of the work; when the body is at rest, it leaves it as heat (excepting such part as is necessary to carry on metabolism, circulation, etc.) If much muscular energy is called for, a deep, full breath is instinctively drawn to supply the oxygen necessary for the added force required.

If strong mental work is required, attention should be given to exercise and deep breathing the while, that the blood may carry off the waste liberated by brain activity. The difficulty is that in doing close mental work, the body is too frequently bent over a desk in such a manner as to restrict the action of the lungs; thus, the brain worker, in order to continue strong, mental work, must often go into the open air,—as he says, “to rest his brain”, but in reality to re-supply the oxygen required to carry on his work and to carry away the waste liberated by brain energy. The supply for the body work has been called upon for the undue brain work, and this lack of oxygen has produced a state of body designated as “tired.” Until the necessary oxygen has been supplied, the brain and body are not balanced, not “rested.”

Nothing is lost in Nature’s distribution of force and energy. Everything accomplished in life, either in the physical handling of material, the brain work in planning the constructions, the mental movements of thought in art, literature, or science, are all representatives of the heat and energy released from the body, and it is the effort of every man and woman to make the body yield as large an income as possible in the expression of this energy. In order that it may do so, it must be used with intelligence, just as any other great machine must be used intelligently; it must be fed, exercised, and rested judiciously.

Repair and Elimination of Waste (Metabolism)

Every part of the body is constantly changing. Its work never stops. If kept in thorough repair it must be torn down and rebuilt incessantly. These chemical changes are called collectively metabolism. They are divided into two groups: the chemical process of building up complex substances from simple ones is known as anabolism; the chemical process of oxidizing and breaking down the complex substances into simple ones, so that they are in a state to be excreted, is catabolism. While the process of oxidation in catabolism is going on, heat and energy are set free. Most of the chemical changes in the body are catabolic in character. This work of tearing down and rebuilding body tissues never ceases—even in sleep.

It is not enough that the proper foods be furnished the body in kind and quantity. The essential thing is that the system be kept in condition to assimilate the foods to its needs and to promptly eliminate the waste. Few people assimilate all of the foods eaten; nearly every one eats more than necessary for the body needs.

By assimilation is meant the digestive process by which foodstuffs are made soluble and diffusible, so that they can pass into the blood; also, the metabolic activity by which the food is converted into cells and tissues.

Nature provides for an incomplete knowledge of the amount of re-supply necessary, by enabling the system to carry off a limited amount of surplus food above the bodily requirements.

The distinct steps in anabolism are discussed in the following chapter describing the work of different organs and the chemical changes of foods as they come in contact with the elements in the digestive juices.

CLASSIFICATION
OF FOOD ELEMENTS

By foodstuff is meant the chemical elements, appropriated by the animal for the use of the body, as described above. By foods is meant those articles of diet found in the market which contain the chemical elements used by the body in various combinations. Bread, for example, contains all of the foodstuffs and has been called the staff of life, because it sustains life. Foods may contain elements, not foodstuffs, and not used by the body, but cast out as waste, while certain foods, such as sugar, cornstarch, olive oil, and egg albumen, contain only one foodstuff, as will be noted in the following classification of foods and foodstuffs—grouped according to the body uses.

There are many classifications but the following tables, as compiled by a leading dietitian[2] for his practical work in classes, are clear and concise.

Carbonaceous foods:
	Sugars
	Starches
	Root and tuberous vegetables
	Green vegetables
	Fruits
	Fats
Nitrogenous foods:
	Lean meat
	Eggs
	Gluten
Carbo-nitrogenous foods:
	Cereals
	Legumes
	Nuts
	Milk

The above classifications are made because of the preponderance of certain elements in them, not because they do not contain other substances; e.g. vegetables are mixtures of sugars and starches; fruits are mixtures of sugars, vegetable acids, and salts; milk, legumes, cereals, and nuts contain a more equal division of sugars, fats and proteins and are therefore represented as carbo-nitrogenous; lean meats, with the exception of shell fish, contain no starch, but all meats contain fat, protein, and water, and all, except liver, contain ash.

In the table below, examples are given of foodstuffs in which the chemical elements are almost pure representatives of their classes. Cornstarch, sago, and tapioca are almost pure starch, containing very little of any other element; glucose, cane sugar, syrups, and honey are almost pure sugar; butter, lard, and olive oil are nearly all pure fat; egg albumen, gluten, and lean meat are almost pure protein.

Foodstuffs		Inorganic		Water		Starches		Corn Starch
				Salts				Sago
								Tapioca
		Organic		Carbonaceous (producing heat & energy)				Glucose
						Sugars		Cane Sugar
								Syrups
								Honey
								Lard
						Fats		Olive Oil
								Butter
				Nitrogenous— (growth and repair)		Proteins		Egg Albumen
								Gluten
								Lean Meat

The proteins contain nitrogen, sulphur, and phosphates. The predominance of nitrogen has given the proteins the name nitrogenous. The carbonaceous foods contain none of these elements, but are rich in carbon, hence the name carbonaceous.

As previously stated, no food contains but one element of foodstuffs and all elements are formed into compounds of plant life from the elements in the soil, air and water by the action of the sun’s rays. The rays of heat and light seem to store something of their power in latent heat and energy within the combinations of these compounds. The end of plant life is the completion of its compounds,—it first generates the compounds, then matures them, and then dies.

All organic matter is thus formed by the action of the sun’s rays upon inorganic matter. All meats are first in the form of plant life and are converted into other compounds by the chemical processes of the animal. This chemical action of the animal converts the energy latent in the foods into more concentrated form. The animal thus performs a part of the chemical work for man.

The classification of foods, as previously stated, is based upon the principal organic foodstuffs contained. Proteins contain carbon and salts, and carbonaceous foods contain salts and nitrogen, but these are not in appreciable quantity. The preponderance of these elements determines the use of the foodstuffs in the body. It will be remembered that the chief uses are the production of heat and energy, the building of new tissue of the growing child, and the repair of the waste in the child and the adult.

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Water

No one element of food is more important for the needs of the body than water. It comprises about two-thirds of the body weight and is a component part of all foods. It is composed of oxygen and hydrogen.

In order that the body may do efficient work in digestion and in the distribution of the nutrient elements of the foods, and that the evaporations from the body may be re-supplied, the water in the foods, together with the beverages drunk, should consist of about seventy-five per cent liquid to twenty-five per cent nutrient elements, or about three times as much in weight as proteins, fats, and carbohydrates combined. If undue evaporation or perspiration is occasioned, a larger proportion is required.

Water passes directly into the circulation without chemical change. It is being constantly evaporated through the lungs and the skin, and every forty-five seconds it passes from the kidneys into the bladder.

The average individual at normal exercise, requires about seventy-one and one-half ounces of water daily, which equals about nine glasses (one glass of water weighs one-half pound); a part of this is consumed in the food. By reference to the following tables it will be noted that water forms a large percentage of all food, particularly of green vegetables and fruits.

The importance of water for children must not be overlooked. It is the heat regulator of the body, and the more energy used, either in work or in play, which results in more heat and evaporation, the more water is required. An animal, if warm, immediately seeks water.

The body will subsist for weeks upon the food stored about its tissues; it will even consume the tissues themselves, but it would burn itself up without water, and the thirst after a few days without water almost drives one insane. It should be furnished freely, in small quantities at a time, to fever patients.

Few people, give much thought to its re-supply; yet they suffer from the loss of it, in imperfect digestion and assimilation, and with kidney and intestinal difficulties, ignorant of the cause.

Water softens and dissolves the food and aids in its absorption; it is one chief agent in increasing the peristaltic action of both the stomach and intestines, thus aiding in mixing the food with the digestive juices and aiding the movement along the alimentary canal; it increases the flow of saliva and of digestive juices and aids these juices in reaching every particle of food more promptly; it aids in the distribution of food materials throughout the body, carrying them in the blood and the lymph from the digestive organs to the tissues, where they are assimilated; it forms a large part of blood and lymph.

The theory has long been held that water drinking at meals is injurious, the objection being that the food is not so thoroughly masticated if washed down with water, and that it dilutes the digestive juices. But this theory is not so strongly held as formerly—in fact, it is now rightly disputed by the best authorities.

When water drinking at meals is allowed to interfere with mastication and is used to wash down the food, the objection is well taken, but one rarely drinks while food is in the mouth, the water being taken at rest periods between mouthfuls. Thorough mastication and a consequent free mixing of the food with saliva is one of the most essential steps in digestion, and the flow of gastric juice, as the flow of saliva, is stimulated by the water.

If, on the other hand, the food is not thoroughly masticated, water is most essential to furnish that which the saliva would otherwise supply to soak up and dissolve the food, in order that the gastric juice may more readily reach all parts of it.

It is singular that the use of water at meals has long been considered unwise when the free use of milk, which is about seven-eighths water has been recommended.

The copious drinking of cool water from a half hour to an hour before a meal will cleanse the stomach and incite the flow of saliva and gastric juice. Moreover, the digestive cells secrete their juices more freely and the sucking villi absorb more readily when the stomach and intestines are moderately full, either of food or water, and to fill the stomach with food requires too much digestion. The water passes through the stomach before the food.

In building up about seven thousand thin women, results show that the free drinking of liquid at meals has a tendency to put on flesh. Probably one reason for this is because of the cleanliness and greater freedom given to the absorbing and secreting cells of the mucous lining of the digestive tract, as well as to the stronger peristalsis.

It will be noted that water drinking at meals has many more arguments in its favor than against it.

One important use to which water is put is to cleanse the digestive tract and the kidneys. This cleansing within is more necessary than the cleansing of the surface of the body. One cannot form a better habit than that of drinking two to three glasses of water upon first arising and then working the stomach and intestines by a series of exercises which alternately relax and contract their walls, causing a thorough cleansing of these organs.

In case of gastritis, or a catarrhal condition of the stomach, often a pint of slimy mucus will collect in the stomach over night and the cleansing of the mucous lining of the digestive tract is then most important.

The drinking of warm (not too hot) or cold water in the morning depends upon the condition of the individual. If in good condition, two to three glasses of cold water, the vigorous exercises for the vital organs, and deep breathing of pure air, followed by a cold bath, will do more to keep the health, vigor, clear skin, and sparkling eye than fortunes spent upon seeking new climates, mineral waters, or tonics. There is no tonic like water, exercise, and fresh air, as above prescribed.

Soft water, that is water containing no lime or other mineral matter, is best for cooking purposes; hard water, which causes any degree of curdling of soap, or a lime crust in the bottom of a tea kettle, is hard on digestion. Bacterial germs are killed and much of the mineral matter deposited by boiling the water. For drinking purposes it should be aerated that it may regain its original, fresh taste, otherwise boiled water tastes flat or insipid. It may be aerated by filling a jar half full of water, leaving the other half for air, and then shaking the water in the jar so that the air passes through it.

Many claim that one’s thirst, as in the desire for food, is the only safe guide, as to the amount and time of drinking, but these desires are largely matters of habit, and tastes are often perverted. Unless the condition is abnormal or the mind becomes so intensely active that one fails to listen to the call of nature, the system calls for what it has been in the habit of receiving and at the stated times it has been in the habit of receiving it. The safe method is to form the habit of eating and drinking a stipulated amount at regular periods and not allowing this regular habit to be broken, unless, for some cause, the system be out of order, and then the habit should only be broken for a time.

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Salt

Milk furnishes salt in proper proportion for the baby, and later, when the child is through nursing, eggs should be added to the diet of cow’s milk. It is especially essential that growing children be furnished milk and eggs that they may be assured of the proper proportion and quantity of calcium salts, as these form the substances of bones and teeth, which constitute about one-sixth of the body weight.

All vegetables, fruits, cereals, legumes, and nuts furnish both calcium salts and sodium, potassium, and magnesium, which are the salts used in the blood and lymph. Minerals are abundant in dried legumes, (beans and peas). A diet consisting largely of vegetables needs the addition of sodium chlorid (common table salt) to supply sufficient salts for foods; likewise more salt than is contained in grass and fodder is needed for animals, particularly for those producing milk. The scientific farmer salts his cattle regularly, while wild animals travel miles and form beaten paths to springs containing salt.

In rectal feeding, it is known that food absorbs more readily through the large intestine if salted. It is probable that salt, in normal proportions, also aids absorption in the stomach and small intestine.

Salt should not, however, be used immoderately.

The minerals of the food, or of the body, form the ashes in burning.

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Iron

Iron is an inorganic substance and is necessary in making red blood corpuscles.

If, by some disturbance in the digestion, absorption, or assimilation of food, more iron is excreted from the body than is made use of from the food, the blood making organs do not receive sufficient iron and the blood is lacking in red corpuscles. It becomes poor in hemoglobin and the individual becomes pale. This condition is known as Anaemia.

Where there are not sufficient red blood corpuscles, it is of vital importance that one keep up a good circulation; the stomach, intestines, liver, and spleen must be strengthened through exercise and one must breathe deeply of pure air, for the red blood corpuscles are oxygen carriers, and the insufficient supply must do double duty or the waste of the system will not be oxidized and eliminated.

A diet rich in iron must be supplied. It will most often be found that one whose blood is lacking in hemoglobin and in the proper proportion of red blood corpuscles, has had a dislike for the foods rich in iron, or, perhaps, has not been able to get the right kind of food.

The yolks of eggs, the red meats (such as steak, mutton or the breast of wild game), and the deep colored greens, (such as spinach, chard, dandelions, etc.) contain a goodly proportion of iron. The dark color of greens and of the dark meats is given to them by the iron which they contain. The dark leaves of lettuce, celery, and cabbage contain iron, but these vegetables are apt to be bleached before being put upon the market.

The yolks of two eggs are better than one whole egg, as the iron is in the yolk. A good way to take the yolk of eggs is in egg lemonade or in eggnog, with a little nutmeg for spice.