CLOTHING OF ANIMALS. 15 



summer dress become thin and suitable. Previous to win- 

 ter, however, and immediately after the process of incuba- 

 tion and rearing of the young is finished, the old feathers 

 are pushed oft' in succession by the new ones, and in this 

 manner the greater part of the plumage of the bird is re- 

 newed. During this process of moulting, the bird seems 

 much enfeebled, and, if previously in a weak state, is in 

 danger of dying during the process. In consequence of 

 this renewal of the feathers, the winter covering is render- 

 ed perfect, and the birds prepared for withstanding all the 

 rigours of the season. In those birds whose plumage changes 

 colour with the seasons, the moulting takes place in sub- 

 serviency to the purposes of these variations, as we shall 

 shortly have occasion to notice. 



By this addition to the non-conducting appendices of tlie 

 skin, quadrupeds and birds are enabled to preserve the heat 

 generated in their bodies, from being readily transmitted 

 to the surrounding air, and carried off by its motions and 

 diminished temperature. But along with a change of 

 quantity, there is frequently also a change of colour. 



2. Changes take place in the Colour of the Clothing:—' 

 The distribution of colour in the animal kingdom, appears 

 to be connected with latitude 'as correlative with tempera- 

 ture. In the warmer districts of the earth, the colours of 

 man, quadrupeds and birds, exhibit greater variety, and 

 are deeper and brighter, than in the natives of colder coun- 

 tries. 



Among the inhabitants of the temperate and cold re- 

 gions there are many species which, in reference to the co- 

 lour of their dress, do not appear to be influenced by the 

 vicissitudes of the seasons. In others, a very marked dif- 

 ference prevails between the colour of their summer and 



