Relation between the Thymus and the Generative Organs. 73 



Experiment' 3 (fig. 1) : Effect of the Removal of the Testes on the Weight of 

 the Thymus and the Growth of the Animal. — This set contained originally 

 7 castrated and 9 normal animals, but owing to deaths only 4 castrated 

 and 6 normals are recorded. The experiment commenced on the day of 

 operation, March 17, and finished on June 24. Here castration seems to 

 have had a positive effect upon growth, but the number of castrated 

 animals (4) indicates the tentative nature of this result. As in Experi- 

 ments 1 and 2 the effect of castration on the weight of the thymus is well 

 marked. 



Animal r>o. 



Days after first weighing. 



Weight of testes 



"Weight of 



0. 



96. 



+ epididymes. 



thymus. | 





Control Animals. 





• 



1 



grin. 

 93 



grin. 

 283 



grm. 

 1 -225 



grm. 

 -190 



2 



109 



322 



1 -235 



0-265 



3 



107 



285 



0-870 



0-175 



4 



165 



420 



2 -100 



0-295 



5 



109 



336 



2 -154 



0-217 



6 



165 



390 



1-750 



-275 





124 



339 



1 -556 



0-246 





Castrated Animals 



1 



148 



412 





0-610 



2 



140 



346 





0-452 



3 



111 



372 





0-430 



4 



124 



391 





-540 





131 



380 





0-508 







Experiment 4 (fig. 1) : Effect of the Removal of the Testes on the Weight of 

 the Thyimis and on the Grovjth of the Animal. — To annul the operative 

 effect the control animals were vasectomised. The experiment started on 

 May 28 and finished on August 1 with 6 vasectomised and 5 castrated 

 animals. The evidence in this experiment with regard to growth is con- 

 tradictory to Experiment 3. 



