88 



GROWTH OF PARTS AND ORGANS 



Body weight on body length. The entire rat was next weighed 

 to one-tenth of a gram. The weight thus obtained was not cor- 

 rected for the contents of the alimentary canal which accord- 

 ing to Jackson and Lowrey ('12) amounts to about 5 per cent 

 of the gross body weight. In gravid females a correction was 

 made however by subtracting the weight of tdie uterus and fetuses 

 from the observed value. The weight of the body on the body 



BOtTY LENGTH 



LENGT 

 nfm. 



60DY WCIGITI 



" m * 

 SS - 355" 



Chart 6 Giving for the males and females respectively the body length on 

 the body weight. Formula (1), table 68. 



length is given in chart 7. The values for each millimeter of 

 body length in each sex are given hi table 68. The graphs were 

 computed by formulas (2a) and (2b), and show that for a given 

 body length the female has a greater body weight. Donaldson 

 '09, Donaldson and Hatai, '11. 



Tail length on body length. The method of obtaining the 

 tail length has been given under body length. The values for 



