II. SIZE OF THE BODY AND ORGANS 



105 



."). Sex differences in weight. 



In the Albino, sex differences in weight are conspicuous in 

 the hypophysis and suprarenals, the gland in the female Ix-in- 

 much heavier in each case. 



In the captive Gray : 



Hypophysis: The sex weight relation changes slightly, 

 giving a somewhat heavier hypophysis in the female captive 

 Gray. This is the Albino relation. 



; TABLE 26 



To show the generations in which low values occur in the several instances 



X indicates a low value. 



Suprarenals: The weight of the female gland is brought 

 closer to that for the male. This is a shift away from the 

 relations for both the wild Norway and the Albino. 



6. All these determinations have been made on animals 

 approximately 600 days old (equivalent to 50 years in 

 human age). The values studied are terminal values, and 

 it is possible to determine only indirectly, as by the effect 

 of unfavorable conditions, at what phase of growth the vari- 

 ous, modifications occurred. 



7. The larger results are these: In only one organ, the 

 thyroid, is there a progressive loss in weight, and this i- ni"-t 

 probably due to food. One organ, the hypophysis, increases 



