320 



E. R. HOSKINS 



c. Thymus, hypophysis, and pineal groups. There is no 

 constant variation of the brain in these groups. There appears 

 to be a sHght tendency to increase in the brains of the hypo- 

 physis-fed group (less marked than in the case of the thyroid), 

 but the difference is not constant. 



7. Eyeballs (tables 4 to 10) 



a. Controls. The absolute weight of the eyeballs in my ani- 

 mals corresponds fairly closely to that of Donaldson's norms (ex- 

 cepting the younger males), as shown in tables 4 and 5. In 

 comparing the relative weights of groups of each sex (tables 

 8 and 9) the eyeballs appear relatively heavier in the older groups, 

 although in these, with heavier body weight, the eyeballs would 

 be expected to be relatively lighter. As suggested by Jackson 



TABLE 4 



Comparison of principal data for control female albino rats with the Wistar tables 

 of Donaldson ('15). Weight is the average expressed in grams. Comparison is 

 made with Wistar norms both of the same body length and of the same gross body 

 weight. 



Body length, cm 



Gross body weight, g. 



Tail-Ratio 



Age (days) 



Organs : 



Brain 



Eyeballs 



Heart 



Kidneys 



Liver 



Spleen 



Lungs 



Alimentary Tract. . 



Ovaries 



Hypophysis 



Suprarenals 



Thymus* 



HOSKINS 



(older) 



19.4 

 171.8 

 0.85 

 213 



grams 



1.781 

 0.276 

 0.737 

 1.379 

 7.530 

 0.751 

 1.900 

 6.966 

 0.053 

 0.011 

 0.049 

 (0.134) 



WISTAR 



(same 



LENGTH) 



19.4 



188.5 

 0.88 



grams 



1.823 

 0.263 

 0.765 

 1.622 

 9.600 

 0.505 

 1.119 

 9.680 

 0.049 

 0.013 

 0.050 

 (0.153) 



WISTAR 



(same 



BODY WT., 



18.9 

 172.6 



grams 

 1.801 

 0.252 

 0.715 

 1.503 

 9.000 

 0.465 

 1.040 

 9.120 

 0.048 

 0.012 

 0.046 



HOSKINS 



(younger) 



18.7 



159.8 



0.86 

 92 



grams 



1.782 

 0.223 

 0.694 

 1.589 

 7.405 

 0.611 

 0.982 



0.064 

 0.010 

 0.049 



(0.264) 



WISTAR 



(same, 

 length) 



18.7 

 166.6 



0.88 



grams 



1.791 

 0.248 

 0.696 

 1.458 

 8.770 

 0.450 

 1.010 



0.048 

 0.011 

 0.045 



(0.278) 



wistar 



(same body 



weight) ' 



18.5 

 160.8 



grams 



1.782 

 0.244 

 0.677 

 1.414 

 8.540 

 0.435 

 0.981 



0.047 

 0.011 

 0.044 



* Thymus compared with regard to age (213 days average for the older group, 

 and 92 days for the younger group) instead of regard to body length or weight. 



