Page:Popular Science Monthly Volume 22.djvu/700

682 by 25,200 grains the 4,800 grains of carbon which, are actually wanted.

C. My carnivorous tendencies, then, may not be so very extravagant, after all. I never ate 6 pounds of lean meat, or a third of that amount. I do not think I have suffered any sort of harm from the nitrogen which I may have taken in excess; I am sure I could never eat 4 pounds of bread, or half that amount, with impunity.

M. There is no occasion for you to eat these monstrous quantities of meat or bread. You must eat 6 pounds of lean meat every day if you take nothing else but lean meat; you must eat 4 pounds of bread every day if you take nothing else but bread; but you may get on very well upon a comparatively small allowance of meat and bread if the two were combined in proper proportions. You want every day 4,800 grains of carbon and 300 grains of nitrogen; you find what you want, as Dr. Pavy shows, in 2 pounds of bread and in about pound of lean meat, thus:

C. I quite shrink from the notion of having to take so much as 2 pounds of bread to make up for the daily waste of my body.

M. You need not take so much, or anything like so much, if you will take fat with your meat, or butter with your bread, or any oily matter in proper quantity. Fat is very rich in carbon, and so are all fatty and oily matters. You would have the 4,800 grains of carbon and the 300 grains of nitrogen which you want, if you took pound of lean meat and about 2 ounces of fat. In proportion as you increase the amount of fatty or oily matter, you may diminish the amount of bread; and, within certain limits, which you may determine for yourself, you may probably please yourself as to the relative proportions of the two. Whether you would get on satisfactorily by excluding bread altogether, and taking fatty matter in its stead, is another question. The growing chick within the egg has plenty of oily matter to feed upon, and nothing of the nature of starch or sugar, or any other carbo-hydrate to take the place of bread. The sucking mammal finds a large amount of oily matter in the milk upon which it feeds, and a somewhat larger amount of lactine, or sugar of milk, which, as a carbo-hydrate, may more or less take the place of bread. In the hen's egg, the proportion of fatty matter to albuminous matter is as 82 grains to 110 grains. In cow's milk the proportion of fatty matter to lactine is as 351 grains to 468 grains, and of these two substances in conjunction, together with caseine, as 811 grains to 369 grains. In 2 pounds of bread and pound of lean meat the proportion of fatty matter to carbo-hydrates is as ·944 ounce to 16·320