"Albumen is the basis of all animal nutrition. This is seen in the bird's egg during incubation. Under the influence of warmth and oxygen, all the tissues, membranes, and bones are developed from albumen."
In the human body a nutritious fluid is prepared from the food, and supplies materials for growth and repair. This fluid is the blood, and when examined under the microscope is found to consist of a clear colorless fluid, of a saline, alkaline, and albuminous nature, and an immense number of infinitely minute blood globules, or corpuscles. These corpuscles consist of an albuminous membrane called globulin, filled with a red coloring matter, hematine, in which there is much iron.
This liquid albuminous portion of the blood must be changed to fibrine before it can nourish the muscles of the body. The change of the gluten, caseine, and all the varieties of albuminous food into fibrine is a gradual process, begun in the lacteals, continued in the circulation of the blood, and completed in the lungs by the oxygen which they receive in breathing. This fibrine remains in the liquid state, owing to the alkaline nature of the blood, and is distributed by the circulation into all parts of the structure, where it gradually coagulates into a network of tough thread-like fibres, enclosing in its meshes the blood corpuscles, and is changed by cell growth into new tissue, solid flesh and bone.
The nervous system is also built and repaired from albumen. Nervous matter is about seven per cent albumen, and is the material by which we are put into relation with the external world. By it we see, hear, feel, taste, smell, and are conscious of existence.
Each elementary cell or particle of tissue, whether of bone, flesh, or nerves, seems to have a sort of gland-like power, not only of attracting materials from the blood, but of causing them to assume its structure and participate in its properties. The bones and teeth select and appropriate the phosphates of lime, and magnesia, also fluorine. The muscles and nerves take fibrine, phosphates of magnesia, and potash. The cartilages seek for soda; the hair, skin, and nails are made up of silica. Iron is needed in the coloring matter of the blood, the black pigment of the eye, and in the hair. Sulphur exists in the hair, and phosphorus in the brains. The glands of the mouth take the substances necessary to form saliva; those of the eye, the elements of tears; the coats of the stomach, gastric juice; and the liver, bile. Each part of the body has the power to select, from the common supply, the material which suits it best for building and growing.
If the conversion of albumen into fibrine be incomplete, the tissues are imperfectly nourished. The formation of tubercles in the lungs is caused by half-formed cells and coagulated albumen deposited in the lungs. This is caused by a deficiency of the oily matter, which is necessary for the perfect formation of cells and the growth of healthy tissue. Hence for these cases physicians prescribe cod-liver oil.
Distilled spirits coagulate the albumen which ought to go into the blood; this prevents the proper digestion of food, and causes one of the great evils resulting from their use. The nervous tissue is thus deprived of nourishment, which is one of the causes of delirium tremens.
Every twinge of pain in neuralgia is the nerves crying out for better blood. Imperfect digestion and assimilation of food are the chief causes of neuralgia.
Nutrition, though seemingly complex, is really a simple process; albumen is changed to fibrine, and fibrine to flesh. The relation of each to the other has been aptly compared to that of the raw cotton, the spun yarn, and the woven fabric.
The minute corpuscles in the blood are constantly building up the body, very much as the coral insect builds its structure. The work of each corpuscle is too small for our conception; but, taken in the aggregate, the result is the wonderful growth and renovation of the human body. And what is still more wonderful, every organ of the body is on the alert to keep the whole system in natural health. The activity of the vessels which remove the waste particles from the blood is untiring. The kidneys are the scavengers of the body, and stand next to the lungs in renovating it. If too much water be drunk, the kidneys, lungs, and skin carry it off, for fear that the blood should become too watery. We may cease to convey food into the body for days with no evil consequences; but let the removing organs cease operations for a single day, and disease ensues.