THE GROWTH-PROMOTING HORMONE 



peritoneal cavity of young growing female rats, 14 days old 

 when the injections were begun. At an age of 75 days, the 

 average weight of thirty-eight injected rats was 228 g., where- 



RE5P0NSE OF THE MALE RATTD CHRONIC INJECTION 

 WITH HYPOPHYSEAL GROWTH HORMONE 



600 



300 



100 200 300 4-00 500 600 



AGE m DAYS 



Fig. 25. — The response of the normal male rat to a growth-promoting extract 

 of the pars glandularis. From Evans and Simpson (1931). 



as that of thirty-eight littermate control rats was 184 g.; 

 therefore, the average weight of the injected group was al- 

 ready nearly one-fourth greater than that of the normal 

 group. More striking differences were obtained in rats in- 

 jected for a longer period. This is illustrated in Figure 25, in 



[87] 



