GROWTH AFTER INANITION FOR VARIOUS PERIODS. 17 



place in the various organs. When animals thus stunted are 

 generously fed, one of three results might be expected concerning 

 their recovery: (i) There might be a complete recovery in the 

 weight of the body as a whole, with normal proportions of the 

 individual organs and parts. (2) Since the growth impulse and 

 the power of maintenance varies considerably in the different 

 organs and parts of the body, one might expect certain individual 

 organs to show lingering effects of stunting. (3) If the stunting 

 were sufficiently severe to lower the final adult body weight, then 

 the different organs and parts might be either similarly or dis- 

 similarly affected. Thus in the first case, an adult of normal size 

 and proportions would be obtained ; in the second case, an adult 

 of normal size but abnormal proportions; in the third case, a 

 dwarf of either normal or abnormal proportions. 



Numerous observations are recorded in the literature on the 

 recovery of the body weight as a whole in different animals upon 

 refeeding after various periods of growth suppression; but very 

 few observations have been made upon the individual organs and 

 parts. A more complete and thorough study of this question 

 seemed desirable, and therefore the present investigation was 

 undertaken. This opportunity is taken to express my indebted- 

 ness to Dr. C. M. Jackson for valuable aid and direction. 



MATERIAL AND METHODS. 



For the present experiments eight litters of albino rats (Mus 

 norvegicus albimis) were used (Table I.), which included twenty 

 males and twenty-five females, a total of forty-five. 



The experiments began when the rats were three weeks of age 

 (time of weaning). From most of the litters, at the beginning of 

 the experiment, one rat of each sex was selected to serve as an 

 (initial) control, the sex being identified by the method of 

 Jackson ('12). Of the nine controls thus selected, two were 

 killed at sixteen weeks of age, and four at about one year; while 

 three were well fed until thirty-nine weeks of age, at which time 

 the experiment for which they were the controls (alternate fasting 

 and refeeding) was discontinued. 



In addition to the direct controls, the observations by Jackson 

 and Lowrey ('12), Jackson ('15) and the Wistar norm tables of 



