HIBERNATION. 



BY SANFORD OMENSETTRR . 



" How wonderful is death ! » 



Death and his brother sleep." 



And, beside, another condition, that of liibernation, has 

 at various times excited the wonder and stimulated the inquiry 

 of observing minds. Sleep and hibernation are similar peri- 

 odical manifestations differing only in degree, and the latter 

 is extraordinary simply because less common than the first. 



Hibernation may be defined as the term used by naturalists 

 to denote that peculiar state of torpor in which many forms 

 of life inhabiting cold or temperate climates pass the wirrter. 

 The influence of cold in producing this state is due only to its 

 tendency to cause sleep, and if carried too far, instead of 

 inducing lethargy leads to death. 



Every phase may be distinguished between ordinary sleep 

 and that profound coma in which the functions of life are 

 almost suspended. In true hibernation, respiration and the 

 production of blood nearly or entirely cease, no food is taken, 

 and the excretory functions are dormant. The circulation, 

 though very slow, is continuous ; the heart beats regularly, 

 and the blood, from the absence of respiration, becomes prac- 

 tically venous. Upon the action of this venous blood alone, 

 circulation depends. In a hibernating animal in which the 

 brain had been removed and the spinal marrow destroyed, the 

 heart has continued to beat about ten hours, while in the 

 same species in a natural state it ceases after two hours. 



Extreme cold will rouse a hibernating animal from its 

 lethargy and speedily kill it, hence many animals congregate 

 in carefully prepared nests, and others, like the snakes, 

 entwine themselves for mutual protection from cold. Most 

 winter sleepers lay up under the skin a store of fat, which is 

 slowly absorbed during the period of their long repose. 



vStibject to an annual lethargy are various species of ani- 

 mals, fish, reptiles, mollusks and insects. This is in many 



