HOW ARCTIC ANIMALS TURN WHITE 63 



truth of Pennant's statement, that the fact of the com- 

 plete autumnal change of the coat in animals that turn 

 white in winter was generally recognised by naturalists. 

 So far as the spring change from the white to the brown 

 dress is concerned, his conclusions are fully confirmed by 

 Capt. G. E. H. Barrett-Hamilton, who communicated some 

 interesting notes on the change in the European mountain 

 or variable hare to the Proceedings of the Zoological Society 

 of London for 1899. The fact that the vernal colour-change 

 is due to the shedding of the coat seems, however, as 

 already mentioned, to have been much more generally 

 admitted than was the case with regard to the autumnal 

 transformation. 



Dr. Allen arrives at the conclusion that both the autumn 

 and the spring change take place periodically and quite 

 independently of the will of the animal, and also that they 

 are but little affected by phases of the weather, although 

 they may be somewhat retarded or accelerated by the 

 prevailing atmospheric temperature. 



So far as the fact of the seasonal change being normally 

 beyond the control of the animal in which it occurs, Capt. 

 Barrett-Hamilton is in full accord with the American writer ; 

 but he goes somewhat further, and believes that it is quite 

 uninfluenced by temperature, or at least by such variations 

 of the same as may be met with in different parts of the 

 area of the British Islands ; and, as we all know, these are 

 considerable ! 



As in the case of many other animals — deer, for instance 

 — the change from the winter to the summer coat takes 

 place very late in the season in the mountain hare in 

 Scotland, specimens undergoing the change being often 

 seen early in May. But the date of the spring change 

 is no earlier in the south of Ireland, where the climate 



