HIBERNATION AND SLOUGHING. 65 



nating in a mass. The second incident mentioned by 

 my correspondent does not refer to hibernation, but 

 simply to the fact that adders do swarm together. 



The physiological condition of a snake when hiber- 

 nating is very remarkable. Eespiration is almost sus- 

 pended, but the heart goes on beating feebly and 

 irregularly. Digestion is totally stopped, and the 

 temperature of the reptile sinks to that of its' sur- 

 roundings — that is, to the temperature of the protected 

 crevice, hole, or heap of leaves, not the temperature of 

 the atmosphere above. If at this stage the snake be 

 disturbed and roused, death usually results. Extreme 

 cold wakes them sometimes, and being unable to per- 

 form their vital processes with sufficient activity at 

 that temperature, they die. No doubt many of our 

 reptiles perish every year from cold in the winter. 



It is a somewhat common belief, and one which 

 is found in many books, that the bite of venomous 

 serpents, if sustained when the reptile is roused during 

 its period of hibernation, is comparatively harmless; 

 and conversely, that the hotter the season the more 

 virulent is the poison. This point was made the sub- 

 ject of observation by l)r Guy on, who comes to a 

 somewhat different conclusion. As the result of his 

 investigations, he is of opinion that the matter of 

 season or external temperature is not the most important 

 factor in determining the degree of virulence of the 

 poison. He finds that the most poisonous bite is that 

 from a poison-gland which has been accumulating its 



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