HIBERNATION AND SLOUGHING. 67 



chemical secretion by the vital activity peculiar to 

 that particular gland. Surely when all the other 

 glands and organs in the body are practically at a 

 standstill, one can hardly believe that the poison- 

 gland goes on secreting just the same, independently 

 of the circulation and other body functions. In this 

 country most observers agree that the adder bite 

 during hibernation is comparatively innocuous, and this 

 conclusion is what one would expect from theoretical 

 reasoning on the physiological condition of the reptile 

 during that period of general functional inactivity. 



Sloughing. — The process of sloughing in serpents 

 is the periodical casting-off of the external epidermic 

 covering. " This moulting of the skin is effected by 

 its being pushed off by the upward growth of fine, 

 temporary cuticular hairs. On certain parts of the 

 body, as on the under side of the capsular skin and 

 scales of the eyes, these hairs do not develop. After 

 the skin is loosened it dries and is readily shufHed 

 off." ^ It is sometimes stated that the sloughing is an 

 annual process, but I think most observers are now 

 agreed that our snakes cast their slough several times 

 every year. The slough, once cast, is said to be used 

 as an article of diet in some species, but I am inclined 

 to think that is more commonly the habit of amphib- 

 ians than serpents, though perhaps the latter also do 

 it. M. C. Cooke expressly states that in the case of 

 the ring snake the slough is left on the grass, and I 



^ Packard. 



