Il8 LLOVDS NATURAL HISTORY. 



winter-dress. Universal in the higher regions of Scotland, 

 this change takes place comparatively seldom in the south ot 

 England, while in the northern counties, although frequent, it 

 is by no means general. Somewhat curiously, the change 

 from the brown to the white dress does not appear by any 

 means always coincident with the advent of winter, or even 

 the approach of cold weather. Stoats having been often killed, 

 even in the south of England, which had undergone a partial 

 change of colour during the early autumn. Mr. Harting states, 

 indeed, that he knew an instance of a pure white Stoat being 

 killed in Monmouthshire in the beginning of August. It is 

 possible, however, that this may have been a case where the 

 ^vhite coat was retained throughout the year ; since, according 

 to Messrs. Harvie-Brown and Buckley, the Stoats on the sum- 

 mit of Ben Nevis are to be seen at all seasons in their white 

 winter-dress. Much discussion has arisen how the change 

 from brown to white in the fur takes place. Bell observing that 

 "this is effected not by the loss of the summer coat and the 

 substitution of a new one for the winter, but by the actual 

 change of colour in the existing fur." This theory has, how- 

 ever, been called in question ; and it is now generally admitted 

 that Macgillivray was right when he attributed the change to 

 growth of new hairs differing in colour from those of the old 

 coat. With regard to the spring change, he writes that "so 

 early as the end of March, and the beginning of April, if the 

 weather be mild, the colour of the upper-parts changes to a 

 dull brownish-red, but the lower remain white, and the black 

 hairs of the extremity of the tail are the same at all seasons. 

 This change is not effected by an alteration in the colour of 

 the same hairs, but by the gradual substitution of brown for 

 white hairs. ... On the whole, it appears to me that in 

 spring, and the beginning of summer, when the animal had 

 assumed its white colour in winter all the red hairs that 



