THE SPLEEN DURING HIBERNATION 



FRANK C. MANN AND DELLA DRIPS 



Mayo Clinic, Rochester, Minnesota 



FOUR FIGURES 



In a study of the ductless glands during hibernation the other 

 organs were observed routinely.^ The most striking changes 

 noted in the hibernating animal occurred in the spleen. 



Polimanti^ in his recent monograph on hibernation mentions 

 the spleen only briefly and there are few references in his com- 

 prehensive bibliography to observations on the spleen during 

 hibernation. It was thought that a note recording our observa- 

 tions might be of value. 



These observations were carried out on spermophiles (S. 

 tridecemlineatus) . The data in regard to length of time torpid, 

 temperature and other important factors of the hibernating 

 animal have been given in detail in another paper' and will not 

 be repeated here. Suffice to state that spleens from 30 hiber- 

 nating animals and a corresponding number from active animals 

 were studied. Of the active animals 12 were killed after vary- 

 ing lengths of time of activity after awakening. This number 

 does not include the animals used in the special experiments 

 reported in this article. The time of hibernation varied from 

 twelve hours to one hundred and seventy-five days. Specimens 

 of the active animals were obtained at various times throughout 

 the year. 



Unless otherwise stated, the active animals were killed by 

 bleeding under light anesthesia. The torpid animals were bled 

 without anesthesia. The specimens were fixed in several fluids, 

 those most used being formalin, neutral formalin, Zenker and 

 Zenker acetic. The sections were stained with hemotoxylin- 



^Mann, F. C. The ductless glands and hibernation. Am. Jour. Physiol., 

 1916, vol. 41, pp. 173-188. 



^Polimanti, O. II letargo. Rome, Bardi, 1913, 683 pp. 



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