Mr. Hainan and Dr. Marshall. 



Animal No. 



Days after first weighing. 



Weight of 



0. 



65. 



thymus. 





Vasectomised Animals. 





1 



grm. 

 245 



grm. 

 387 



grm. 

 433 



2 



230 



424 



0-400 



3 



268 



467 



0-500 



4 



173 



282 



0-254 



o 



203 



373 



U oUU 



6 



170 



400 



0-393 



Average 



215 



389 



-380 





Castrated Animals. 





i 



243 



330 



0-573 



2 



280 



405 



-607 



3 



210 



353 



-738 



4 



147 



320 



-545 



5 



157 



336 



0-614 





207 



349 



0-615 



• = Castration. 



Time in days. 



Is0 ' ^ 35 ii so 60 70 80 



Fig. 1. — Effect of Castration on the Growth of Guinea-pigs, 

 e curves are formed from the averages of the individuals of Experiments 2, 3, and 4.) 



