Page:Popular Science Monthly Volume 1.djvu/324

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starch in its respiratory equivalent of fat, i. e., 390 parts meat and 126 fat, he eliminates daily only 28.3 parts solid matter, with 2.6 of nitrogen; while on the contrary, the liquid excretion holds 14.2 if nitrogen. Consequently, though the amount of albumen in the two cases was the same, still twice as much of it was absorbed by the intestine from the ration of meat as from that of vegetables. The 800 parts of meat yielded only 27 of dry residuum.

This difference in absorption makes the essential difference between vegetable and animal food. Consequently, we are not justified in saying that 2.4 of starch is the equivalent of one part fat. Further, 1 part fat and 2.4 albumen, both absorbed by the same organism, have not the same action on the transformation of albumen or the admission of oxygen. Great caution must therefore be observed, in treating of such equivalencies, even where the elements of nutrition are analogous, but come from diverse sources. Their mutually different behavior in digestion has not been always taken into account.

Dr. Hoffmann has studied this subject for the human economy, as regards various alimentary substances or nutritive elements. Bread, potatoes, rice, maize, etc., taken in any quantity whatsoever, can scarcely support the life of man or of carnivorous animals, communicating to them no bodily strength. Too large a proportion of their nutritive elements is eliminated in the excretion. Still, with the addition of a small quantity of albumen, whether animal or vegetable, they may suffice. They are poor in albuminates, but rich in starch. Even herbivorous animals often take in an excess of food, so as to get the requisite amount of albumen.

The same occurs with man, and therefore he will waste non-azotized material. The quality of the food he takes may be told from the excreta. It is Liebig who said that you might make out the boundary-lines of those countries where the coarse brown bread of Westphalia is used, from certain indications found along the hedge-rows. An Irish laborer, according to Buckle, consumes daily 9½ lbs. of potatoes, a weight too great for all the intestines to carry. These potatoes would contain of water 3,200 parts, dry albumen 70, and of non-nitrogenous substances 725. The latter quantity is far in excess of what is necessary to nourish a strong man; but there is a deficiency of albumen, to say nothing of the amount lost in the excreta. As a consequence, the body is capable of but little work, notwithstanding the great quantity of potatoes taken in, and it is but ill provided with the means of resisting disease, owing to the excess of water in the organs. The same is to be said of rice, which is poor in nitrogen. According to Salvatore Thomassi, the farmers of the rice-fields in Italy, who enjoy liberal fare, reach an advanced age, while the day-laborers who live on rice succumb prematurely to diseases caused by exhaustion. In Western India, where rice is the chief food of the natives, they always add some element of food which is richer in azote. Those Italian laborers