392 DAVID E. FINK. 



beetles during the winter, produced a mortality of 100 per cent. 

 In this species a reduction of the water content probably does 

 not proceed to a sufficient degree to prevent injury by freezing 

 temperatures, hence necessitating their further protection by 

 burrowing in the ground. 



During the progress of hibernation, continued investigations 

 have shown that the water content remains practically constant, 

 although with a general diminution of fat, a slight increase in 

 the water content may follow. Extremely significant is the 

 excessive depletion in fat that obviously takes place during the 

 first two months (51 per cent.) as compared to the remaining 

 five months (49 per cent.) of hibernation. 



In this connection it is of interest to cite, for comparison, the 

 results of other investigators concerning fat consumption during 

 hibernation. Victoroff (26) with frogs found a consumption of 

 23 per cent. Investigators with mammals demonstrated the 

 prevalence of a large fat content which gradually disappears 

 during the period of torpidity. Thus Voit (27) found that in 

 the marmot the adipose tissue was more than 30 per cent, of 

 the weight of the body. Valentin (25) found the adipose tissue 

 in the marmot contributed about twenty times as much food as 

 the hibernating gland. He also observed that the depletion in 

 fat which occurred during the first few months was greater than 

 after five months hibernation. Similarly Carlier (8) found that 

 almost one half of the fat disappeared in the hedgehog during 

 the first few months of dormancy. It is of interest to discover 

 this general conformity between a mammal and an insect in the 

 utilization of nutrient material during the course of hibernation. 



Hibernating Gland. 



Many investigators mention a hibernating gland which is said 

 to be commonly found in mammals (hedgehog, marmot, bat, 

 shrew, rat, mole, beaver, squirrel, weasel, martin, badger, rabbit, 

 guinea pig, cat, dog and even in man). Rasmussen (18) who 

 has reviewed the literature on this subject extensively, is of the 

 opinion that it is distinct from adipose tissue. Sheldon (22) 

 recently concluded that "the so-called hibernating gland is 

 essentially a form of adipose tissue which retains its embryonic 

 characteristics for a more or less indefinite length of time, . . . 



