HIBERNATION. 



795 



These results have been extended and confirmed by Marshall Hall, 1 Kegnault 

 and Keiset, Horvath, 2 and others. 3 



Kegnault and Eeiset 4 determined the respiratory exchange of several 

 hibernating marmots, and found that the intake of oxygen was about 

 one-thirtieth of that of an active animal, and only about two-fifths of the 

 oxygen appeared in the carbon dioxide discharged. The following are two 

 examples : 



A further proof that oxygen was stored up in the body of the hibernating 

 animal was found in the increase in weight of a marmot during profound 

 torpidity; it gained as much as 5 '9 grins, in five days. 



The output of carbon dioxide was investigated by Horvath, who found that 

 the amount varied according to the animal's activity. The following is an 

 example of his results : 



Similar results have been obtained in the case of dormice and bats. 6 

 According to Saissy, 7 a hedgehog can absorb all the oxygen from the 

 air in which it is confined, and can even live for fifteen minutes in pure 

 nitrogen, whereas a rat under similar conditions dies in less than three 

 minutes. 



Circulation. The force and frequency of the heart-beat is much reduced 

 during hibernation ; in the case of the bat and dormouse to fourteen and 

 sixteen per minute or even less, the rate in the active animal being above 100 

 per minute. On applying a stethoscope to the chest of a hibernating bat, 

 no sound of the heart-beat can be heard, whereas, when the animal awakes and 

 becomes active, the sounds are so loud that they can be heard by the ear placed 

 one inch away from the animal (Hill and Pembrey). 



1 Phil. Trans., London, 1832, pt. 2, p. 335; Barkow, " Der Winterschlaf," 1846, 

 here numerous additional references are given. 



2 Verhandl. d. phys.-med. Gesellsch. in Wurzburg, 1878, Bd. xii. ; 1879, Bd. xiii. ; 

 1880, Bd. xiv. ; 1881, Bd. xv. 



3 Pembrey and Hale White, Journ. Physiol., Cambridge and London, 1895-96, vol. 

 xix. p. 477. 



4 Ann. d. chim. et phys., Paris, 1849, Ser. 3, tome xxvi. p. 429. 



5 Allied to the marmots. 



6 Pembrey and Hale White, loc. cit. 



7 Deuteches Arch. f. d. Physiol., Halle, 1817, Bd. iii. S. 135. 



