THE VARIATIONS DURING LIFE 



TABLE XXXII. 



125 



The dormouse was coiled up and fast asleep at the end of the 

 experiment. 



Observations and determinations have been made also by Hari 

 [1909, i] on the bat. At fairly high temperatures bats show the usual 

 " chemical" heat regulation, but when the temperature falls below a 

 certain point, differing according to the animal's state of nutrition from 

 1 9 to about 1 2, the movements cease, and a state of torpor develops 

 resulting in a rapid fall of the body temperature. 



It is known (Merzbacher [1904]) that hibernating animals have 

 normally a labile temperature, which usually falls considerably during 

 ordinary sleep. The temperature of bats especially will fall during 

 their sleep in the daytime to a few degrees above that of their sur- 

 roundings. 



It appears to follow from the data given that in hibernating animals 

 low temperatures do not necessarily produce muscular movements 

 through the heat regulating mechanism of the central nervous system, 

 and that the immediate cause of the fall in body temperature is simply 

 that the standard metabolism of these animals at a comparatively high 

 surrounding temperature becomes insufficient to cover the loss of heat 

 and therefore to maintain the temperature. Further experiments on 

 the gas exchange of animals going into hibernation made by means of 

 Benedict's recording cage, and also on such animals under curari, are 

 very desirable. 



It is known that during the hibernation, when the sleep is deep, the 

 respiratory exchange rises and falls with the temperature just as in a 

 cold-blooded animal. The most reliable figures have been given by 

 Nagai [1909] for the marmot, but an extended investigation is re- 

 quired. 



