COLOUR IN BIRDS AND QUADRUPEDS. 225 



contain the rudiments or sheaths of the feathers. The hair, like fea- 

 thers, is nourished and receives its colour from the secretions of the 

 animal, and is exposed to the same sun, air and moisture. It continues 

 to grow during a certain period, and drops off when it has arrived to 

 full maturity, as do the feathers from the bird, and the leaf from the 

 tree. There is also a striking similarity between the covering of birds 

 and quadrupeds, in the changes to which they are subject, from the 

 young to the adult state, and the mutations of others during the differ- 

 ent periods of the year. As the majority of the species of young birds 

 are of the colour of their parents, so are the young of quadrupeds. 

 Some young birds remain for a length of time of a very different co- 

 lour from that which they assume when they arrive at maturity, as is 

 the case with some of the species of our Fringillge, Jlrdex, and other 

 genera. This is also apparent in some of our quadrupeds. The young 

 of the Deer and Cougar (Felis cougar), for instance, are striped or spot- 

 ted with white and red, whilst their progenitors are of a uniform dun 

 or fawn colour. Some birds are disguised in two such opposite sets of 

 colours, in the course of the year, that the gay visiter of spring can 

 scarcely be recognised under his homely dress in autumn. So also our 

 Ermine, and two, at least, of our species of Hares, are brown during 

 six months of the year, and of a snowy white pelage during the other 

 six months. Bearing so strong a similarity in many other particulars, 

 we are led to believe that in the process of moulting, or shedding of 

 the hair, this harmony of nature still continues to prevail. 



Here, however, the same difference of opinion has obtained among 

 naturalists. Probably much has been written on the subject in Euro- 

 pean journals which has not fallen under my observation. Dr Flem- 

 ming (see Philosophy of Zoology, vol. H., p. 24) advances an opinion, 

 the result of personal observations, that " the change of colour in those 

 animals which become white in winter, is effected, not by a renewal 

 of the hair, but by a change in the colour of the secretions of the rete 

 mucosum, by which the hair is nourished, or perhaps by that secretion 

 of the colouring matter being diminished, or totally suspended." This 

 theory, as far as I have been able to ascertain, has generally been adopt- 

 ed by physiologists. I have also noticed the remarks of Dr Richardson, 

 on the changes in the colour of the American Hare (Lepus Jlmerica- 



