104 



THE NATURE BOOK 



I do not know that any reliable in- Dormouse and Hedgehog, whose winter 

 vestigations have yet been made of the quarters are above ground level, such a 

 circumstances attending normal hiber- contingency is by no means impossible. 



It is inconceivable, 

 from a mechanical stand- 

 point, that either of these 

 highly organised animals 

 could survive being actu- 

 ally frozen. We must 

 assume, therefore, either 

 that extreme cold will 

 rouse them (in the Hedge- 

 hog a body temperature 

 of 38° F. has been re- 

 corded), or, as is more 

 likely, that there is some 

 working source of heat 

 within their bodies which, 

 shght though it may be, 

 is yet sufficient to keep 

 their body temperatures 

 under all circumstances 

 above 32° F. 



I cannot regard the 

 TK .. 1'^^r'l'''^? "^""fA^^^f-, . usual explanation, that 



The attitude is designed to shield the vital organs. ^ ' 



nation in animals. The investiga- 

 tion is. in any case, an extremely 

 difficult one, and one of the most 

 interesting points in connection 

 with it, the determination of the 

 body temperature of the animal 

 in relation to the temperature of 

 the surrounding air, must always 

 involve the risk of gravely dis- 

 turbing the normal conditions, 

 if not, indeed, of kilhng the 

 animal outright. 



Such evidence as exists seems 

 to show that the body tempera- 

 ture of a hibernating animal 

 corresponds fairly closely with the 

 temperature of the surrounding 

 air, so that we have the remark- 

 able phenomenon of a warm- 

 blooded animal assuming, during 

 certain definite periods of its 

 existence, one of the peculiar 

 characteristics of a cold-blooded 

 animal. 



The question as to what hap- 

 pens when the temperature of the 

 surrounding air falls to freezing 

 point will naturally present itself, 

 and it must be remembered that, 

 in the case of animals like the 



DOKMOUSE. 



Showing the bushy character of the tail and the apparent 

 shortness oi the limbs. 



