SOME RELATIONS BETWEEN GROWTH 

 AND NUTRITION 



IT is unnecessary to point out that growth is one of the most 

 important and fundamental phenomena with which we have 

 to deal. Numerous problems suggest themselves in this con- 

 nection, and they may be approached from diverse viewpoints 

 each of peculiar interest. We may say at once that the possibili- 

 ties of growth, and the capacity to grow, are determined by 

 heredity, and are strictly limited. We are convinced, therefore, 

 that we may attain a certain size, but that size is determined by 

 heredity and there is no possibility of ever exceeding a certain 

 maximum. There are giants in the world, but no one knows the 

 secret of producing giants at will. We assume, then, that there 

 is a more or less definite point beyond which growth may not 

 proceed ; so we should stress the fact that this maximum (or 

 optimum possibility) may not be attained, due to some limita- 

 tion of the environment. It is with one phase of the environ- 

 ment that we are now chiefly concerned, and that is the food 

 supply, its composition, and amount. 



I. The Nutrients Now Recognized as Suck 



At this time we shall only concern ourselves generally with 

 the substances that are considered as nutrients for the animal 

 body, and specifically with the following: proteins, fats, carbo- 

 hydrates, minerals, and vitamins. 



We have purposely left out some substances that might prop- 

 erly be included, such as oxygen and water, and there may be 

 others as yet unrecognized. So we will add "etc." in order to 

 be sure that nothing is omitted. After this brief introduction, 

 we shall proceed to a discussion of these groups of compounds 

 individually, and to some extent collectively, with regard to 

 their roles in nutrition, and shall begin with the proteins. 



