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ages. The yolk and white of the egg gradually 

 become thinner, supplying the growing chick 

 with nourishment, which, increasing in magni- 

 tude, at length bursts its cell and. comes forth, 

 still retaining in its intestines a portion of the 

 yolk to serve for its support, until its powers are 

 sufficiently vigorous to enable it to digest extra- 

 neous food. 



It is a remarkable fact, that those birds, the 

 nests of which are most uncovered, and the eggs 

 of which are most exposed to the sight of their 

 enemies, lay them of a colour as little different 

 as possible from surrounding objects, so as to 

 deceive the eyes of destructive animals ; whilst, 

 on the contrary, those birds, the eggs of which 

 are of a deep and vivid colour, and consequently 

 very liable to strike the eye, either hide the nests 

 in hollow trees, or elsewhere, or do not quit their 

 eggs except at night, or commence their incuba- 

 tion immediately after laying. It must, more- 

 over, be remarked, that in those species, the nests 

 of which are exposed, if the females alone sit 

 on the eggs, without being relieved by the male, 

 these females have generally a different colour 

 from that of the male, and more in unison with 

 neighbouring objects. 



All providing nature, says Monsieur Gloger, 

 a distinguished German naturalist, and the first 

 observer of this remarkable arrangement, has 

 thus consulted the preservation of the species, 

 the nests of which are altogether exposed, by 

 giving to their eggs a colour incapable of betray- 



