176 



GROWTH IN TOTAL BODY WEIGHT 



weights have been computed for each day of age from 10 days 

 on see table 157. 



The values given for the first ten days of age in table 157 

 have been obtained from a revised series of direct observations 

 Donaldson ('15). 



The weight at birth as here given, is for rats that have suckled. 



Using a group of 148 males and 158 females, composed of 

 animals which were specially well cared for and fed, Greeman 



Body weight in grams - - 



:: 



Growth in body weight 

 on age. Females 



. 



/ 



Age in days 



J_LL 



K> ZO JO 50 M 70 80 SO 100 IK) 120 130 MO 150 l<0 170 180 190 



10 220 30 IV ZSJ MO Z70 iK> no 300 JIO OT 330 



Chart 22 Growth of body weight on age. Female albino rat. A. Observa- 

 tions of Donaldson, Dunn and Watson ('06). See table 157. B. Observations 

 of King ('15). Data from two series combined. See table 121. 



and Duhring ('23, page 4, chart no. 1) have recorded a growth curve 

 for the males which after a hundred days shows higher values 

 than those just given. At 350 days this special group surpasses 

 our male values by 65 grams and the curve is still rising. 



In the case of the females the superior treatment and food pro- 

 duce animals which are about 15 grams heavier at 100 days and 

 about 18 grams heavier at 350 days. As so often happens the 

 greater response is given by the males table 157 a. 



