NATURAL HISTORY STUDIES 



Apart from the state of latent life in which a 

 paste-eel, for instance, may lie neither actively 

 living nor really dead for fourteen long years, and 

 seeds for much longer there is no form of sleep so 

 near to death as this to which the Wizard of the 

 North commands the true hibernators. The heart 

 of the hibernator beats feebly and somewhat 

 irregularly, the breathing movements are at long 

 intervals and very sluggish, the food-canal is empty, 

 income is (apart from oxygen) at zero, and expendi- 

 ture is but little more. The fat, accumulated in 

 days of plenty, is slowly burnt away, sustaining 

 in some measure the animal heat. In the hibernating 

 mammal the power of keeping an almost constant 

 body -temperature has broken down for a time, and 

 the body cools greatly ; the sleeper will hardly 

 answer back to anything, even to a cold bath ; the 

 creature steadily loses weight. The real wonder is 

 that it keeps alive. In most cases its safety depends 

 on getting into some snug retreat or well-blanketed 

 confined space, to the temperature of which its 

 own body -temperature approximates. In an ex- 

 posed situation the sleeper would die. 



The general meaning of winter-sleep is in most 

 cases plain. Life saves itself by ceasing to struggle, 

 by retiring within its entrenchments. Death is 

 baffled by a deep device, in which activity practically 

 ceases without life itself being surrendered. Hiber- 

 nation is the finest illustration of the value of 

 " lying low and saying nothing." 



Yet there are other aspects of the winter's sleep. 

 To some it is a time of repair a long night after 



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