244 E. V. McCOLLUM 



our colony, with a series of diets comparable to the several types employed 

 by man in different parts of the world, will serve to clarify the whole 

 subject of the relation of the diet to development. 



It has been shown by many tests that a diet consisting solely of 

 cereal grains such as whole wheat kernel, maize, oat, barley and rye, 

 together with the protein-rich legume seeds, peas and beans, and soy 

 beans, fails, irrespective of its complexity or chemical composition, to 

 satisfactorily nourish a growing animal. Even the above list of foods can 

 be supplemented with f ruits and such tubers as the potato, and such fleshy 

 roots as the sweet potato, radish, turnip and beet, and with any desired 

 amount of a muscle cut of meat such as round steak, ham, roast, etc., with- 

 out making it satisfactory for a growing animal or for the maintenance of 

 normal health and vitality in an adult. This list of foods forms the basis 

 of a diet consisting of steaks, chops or roasts, potatoes, peas, beans, fruit, 

 pies, etc., which is so commonly served in American homes at the present 

 time. This statement seems most surprising but it rests upon an abundance 

 of experimental evidence, not only with animals but upon human ex- 

 perience as well. 



The faults in such a diet involve three and to some extent probably 

 four dietary factors. The first in magnitude of importance is the shortage 

 of calcium, and but little less serious from the physiological standpoint 

 is the deficiency of sodium and chlorin. Next in importance is the lack 

 of sufficient fat-soluble A to meet the needs of a growing mammal. The 

 fourth dietary factor which is undoubtedly below the optimum in such 

 a food mixture is that which may be designated as the antirachitic factor, 

 because it is so intimately concerned with the development and functioning 

 of the osteoblast, and consequently with bone development. When these 

 faults in any seed, tuber, fleshy root and muscle meat mixture are cor- 

 rected by suitable additions, it becomes a satisfactory diet for the pro- 

 motion of growth and the maintenance of vitality. 



It is possible to correct the inorganic deficiencies in a diet such as 

 may be derived from the list of cereals, fruits, legume seeds, tubers, fleshy 

 roots and muscle tissue, only by the use of liberal amounts of milk or of 

 leafy vegetables, or by the direct consumption of bony substance or other 

 source of calcium such as the carbonate, together with common salt. The 

 omnivorous and herbivorous animals follow one of these practices for the 

 completion of their diet, or fall below the normal level of nutritional 

 stability within a short time. The carnivorous animals and carnivorous 

 man secure the same result by the consumption of blood, which is rich 

 in sodium chlorid, and a certain amount of bone for its calcium, and enrich 

 their food with fat-soluble A by ingesting glandular organs, which are 

 good sources of this dietary factor. The leaves of plants and the fat 

 of milk, butter fat, are also excellent sources of this dietary essential. 



The statement made in the preceding paragraph may be put in an- 



