374 STUDIES OF NATURE. 



ing with the exceptions which wife Nature has in- 

 troduced and eftabhfhed, for the very prefervation 

 of animals; fuch as, in general, the whitening of 

 them, to the North, in the Winter feafon, and on 

 lofty mountains, as a remedy againft excefs of cold, 

 by arraying them in a colour which reflecfls the 

 mod heat; and embrowning them to the South, 

 during the ardors of Summer, and on fandy dif- 

 triâis, and thereby flieltering them from the effefts 

 of burning heat, by the intervention of abforbent 

 colours. What evidently demonftrates, that thefe 

 great effefls of harmony are not mechanical refults 

 of the influence of the bodies which furround ani- 

 mals, or of the apprehenfions of the mother on 

 the tender organs of the foetus, or of the adion of 

 the rays of the Sun on their plumage, according 

 to the explications hitherto attempted by our fyf- 

 tems of phyfics ; what evidently demonftrates 

 this, I fay, is, that among the almoft infinite num- 

 ber of birds which pafs their life in the higher 

 regions of the air, or on the furface of the Seas, 

 whofe colours are azure, there is not a fingle bird 

 of the colour of blue ; and that, on the contrary, 

 many birds which live between the Tropics, in 

 the bofom of black rocks, or under the (hade of 

 fullen forefls, are azure-coloured : fuch are the 

 Batavia hen, which is blue all over; the Dutch 

 pigeon of the Ifle of France, and many others. 



Another 



