Page:Popular Science Monthly Volume 79.djvu/594

590 of albumins, carried out largely during the past two decades, have taught us that albumins are composed of simpler substances, termed amino-acids; the different native albumins are composed of many amino-acids in different proportions; and all the chief plant and animal albumins are in general composed of the same amino-acids, though in different proportions. These amino-acids we term the "building-stones" of albumin, and, as stated, the plant albumins contain all the essential amino-acids, the same building-stones that are contained in the animal albumins. When an albumin is digested, it is split (torn down) into the component building-stones. These buildingstones are then absorbed, and with these the body, displaying a specific biological selection, builds or forms its own peculiar albumins. In other words, the building-stones are common to all albumins, the chemical and biological differences in the albumins rest in the architecture and not in the building-stones. Many types of houses may be constructed of brick of a common type; and so many kinds of albumin are formed of building-stones of common types; and from the common albumins of plants all the building-stones needed in the formation of the human albumins are to be obtained. It is clear therefore that it is quite immaterial to the human body whether it forms its tissue albumins from amino-acids derived from the digestion of animal or plant albumin, i. e., these are equivalent in their nutritive values. These purely physiological and chemical data, abundantly sustained by laboratory researches and animal experimentation, confirm as well as elucidate the now widely made human experience that a properly selected and prepared vegetarian diet is a complete diet for all conditions and periods of life, beyond the lactation term of infancy.

Is a purely vegetarian diet better than a mixed diet, a diet containing a reasonable amount of albumin of animal origin? To make the question physiologically fair (since meats are often hugely overeaten), the ration of albumin in the two diets must be such as scientific investigations have shown to be sufficient and normal. Possibly a gram of albumin per kilo of body weight per day (equivalent to eleven ounces of meat per day for a body of 150 pounds) may be accepted as the normal total ration of albumin. There are absolutely no data of scientific nature or reliable observations in practical experience tending to show that either of these diets is in any way preferable physiologically to the other. It is apparently immaterial to the body of a hundred and fifty pounds whether in a properly selected and prepared diet the 2.2 ounces of albumin are exclusively of plant origin or partly derived from flesh. Since all cereals and vegetables contain albumin, a mixed diet always contains both plant and animal albumin, the ration of the latter of which would naturally run six to eight ounces of meat per day. I have used the words properly selected and prepared. It is obvious that