THE SPLEEN DUEING HIBERXATION 279 



fixed in formalin and the section stained with Scharlach R for 

 fat. Rarely were fat droplets found in any of the cells of the 

 organs of active animals. In several of the spleens of torpid 

 animals, certain cells were found containing fat droplets. These 

 cells, usually few in number, were large lymph cells which were 

 always found in the germ centers. We have never observed 

 fat-containing cells in any other part of the spleen. 



In the spleen of the active spermophile there can always be 

 found a considerable number of phagocytic endothelial cells con- 

 taining red blood corpuscles or blood pigment. In the con- 

 gested spleen of the animal which has been torpid for only a 

 short length of time there seems to be a marked decrease in these 

 cells. Owing to the marked congestion it may be that this is 

 only a relative decrease or the cells are masked by the large 

 amount of blood present. However, in some of the organs of 

 animals which had been torpid less than forty days we were not 

 able to find any of these cells. They reappeared in the animals 

 which had hibernated longer and were still more numerous in the 

 active animals which were killed within a short period after 

 awakening. How^ever, the largest number have always been 

 found in the active animals. 



Some of the torpid animals were killed without bleeding. 

 The congestion of the spleen did not seem to be greater in these 

 animals than in those which were bled. 



Some experimental procedures were employed in the attempt 

 to reproduce in the active animal the picture of the spleen found 

 in the torpid animal. Some animals were killed with ether and 

 about fifteen minutes after death the spleen was carefully 

 removed and fixed. Other spermophiles w^re asphyxiated either 

 in a closed jar or with illuminating gas. Some animals killed 

 by the latter method were asleep. In some experiments the 

 venous outflow was impeded for a short period before death. 

 While most of the spleens in animals subjected to these experi- 

 mental procedures showed congestion, it was impossible to 

 attain completely the intense congestion noted in the organ of 

 the animal which had been torpid for only a short period of 

 time. 



