150 THE AMINO ACIDS 



which may be employed for the attainment of a type 

 of animal infantilism. In connection with the sub- 

 ject of stunting it became of interest to determine 

 whether this condition would remain permanent under 

 all circumstances or whether a return to a diet con- 

 taining a more typical protein than gliadin would also 

 cause a resumption of growth. Fig. 8 shows the 

 slight growth of a young white rat during 276 days 

 of gliadin feeding. That the capacity to grow had 

 not been lost, but was merely inhibited, may be seen 

 in the second part of the curve in which milk food 

 replaced the gliadin. At the beginning of the milk 

 food diet the rat was 314 days old, an age at which 

 rats usually show very little growth. Fertility is not 

 impaired by the act of stunting, as may be seen from 

 the curve in Fig. 9, for this rat, after a period of 154 

 days with gliadin as its protein supply, was mated 

 and produced four young, which were suckled during 

 the first month of their existence by the mother who 

 was still maintained upon a gliadin diet. These young 

 rats presented normal growth curves during this 

 period. When a month old, three of the young ani- 

 mals were removed from the mother and kept upon 

 diets of casein, edestin, and milk food. All showed 

 normal curves of growth. The fourth young rat, 

 kept with the mother began to exhibit a failure to 

 grow as soon as forced to depend upon the gliadin 

 food mixture. Inasmuch as casein, which has been 

 proved to be efficient as a source of nitrogen for both 

 maintenance and growth, is lacking in glycocoll, 



