IHIBERNATION AND SLOUGHING. 73 
on what the reptile happens to rub itself against in its 
effort to rid itself of what has become an incubus. 
Should the adder happen to find itself evenly wedged 
in between two stones, or to have equable pressure 
exerted upon its sides in crawling through a thick 
bush, then the slough will peel off entire. But the 
slough is a most fragile and delicate substance, ex- 
tremely easily torn, and it must very frequently 
happen that at one stage or other of the shedding 
a portion will be ruptured by catching against some 
contiguous thorn or stone or bramble. When this 
takes place the resulting slough will not be in one 
piece but in sections. I have captured a large number 
o, and in nine out 
of adders while they were sloughing, 
of ten cases the slough was torn partially off before 
the process was completed. I think this a very usual 
oceurrence, quite apart from the healthy condition or 
otherwise of the adder. Adders cast their slouglis, 
as a rule, at least three times every summer, and | 
have observed that the female is very often under- 
going the change of cuticle just before the birth of 
her young. The tail slough comes off very easily, and 
is not turned inside out, as a rule, though it frequently 
is in males. I have on several occasions, after taking 
an adder that was sloughing, tried to complete the 
process as one would skin an eel, and on each occasion 
part of the slough came off in my hand, proving how 
slight a force is sufficient to tear it in pieces. More- 
over, though I have frequently found pieces of adder 
