280 FRANK C. MANN AND DELLA DRIPS 



The adult spermophile usually withstands operation very well 

 but removal of the spleen proved to be an exception. Most 

 of the animals died within a few weeks after splenectomy, but a 

 few^ lived for several months. Careful observation showed that 

 these splenectomized animals hibernated under the same 

 conditions as the controls. 



The intense congestion of the hibernating spleen is probably 

 due to a loss of tone and relaxation of the intrinsic muscles of 

 both the spleen and the blood vessels. A consideration of the 

 part this plays in the phenomena of hibernation must be purely 

 speculative. It is possible that the spleen acts as a store room 

 for the red blood cells in the early stages of hibernation and 

 allows them to be added to the circulation as needed. The fact 

 that the corpuscles in the congested sinuses appear perfectly 

 normal and that phagocytosis of the red cells seems to be de- 

 creased and not increased as one would anticipate, strengthens 

 this idea. However, the fact that splenectomized animals 

 hibernate normally shows that this is only a secondary factor. 



