COMPENSATORY HYPERTROPHY OF THE TESTES. 



463 



any of the five control pairs with one slight exception (No. 64). 

 These results cannot be due to chance; we are therefore justified 

 in concluding that a surviving left testis, the partner of which is 

 removed at one week after hatching, exhibits a much greater 

 amount of growth than it would have done, approaching in 

 some cases twice the normal growth. 



Preliminary histological examinations of sections of hyper- 

 trophied testes indicate that all the gonad tissues are equally 

 concerned in this increase in size. 



TABLE II. 



RESULTS OF I'MLATICKAI. ("ASIKAIIOX AI H. WKKKS. 



All weights are in grammes, 

 to total weight of bird. 

 1 c = control. 



Per cent, weight = percentage of weight of testis 



