218 



the shell, and remains till it comes to its full size. The 

 parent then broods over it, till the young being gra- 

 dually formed, perfected, and quickened, bursts the 

 shell. 



Under the shell of an egg lies the common mem- 

 brane, adhering closely to it, except at the bigger 

 end, where a little space Is left between them. This 

 membrane contains two whites, each enclosed in its 

 own membrane. In the middle of the inner white 

 is the yolk, enclosed likewise in a separate cover. 

 The outer white is oval, the inner round, (as is the 

 yolk) and of a more viscid substance. 



At each end is a chalasa, a white, dense body con* 

 sisting of three little globules, like grains of hail, (so 

 the word signifies) all joined together. These serve, 

 both to knit the several membranes together, ancl 

 to keep the liquors in their proper places and po- 

 sition. 



About the middle of the small end of the yolk, is 

 a little yellowish bladder, like a vetch, called the 

 cicatricula, or eye of the egg. This contains a hu. 

 monr, in and out of which the young bird is generated, 

 The white serves it for food, till it becomes big : then 

 the yolk, and likewise after it is hatched. For even 

 then a good part of the yolk is lodged in its belly, 

 as in a store-house, and being conveyed thence by 

 the intestinal duct into the bowels, serves it instead 

 of milk. 



An egg, impreperly so called, is that, of the whole 

 whereof the animal is formed. Such are the eggs of 

 flies. Proper eggs, when excluded need no external 

 nutriment Of proper eggs, some are perfect, that 

 is, have all the parts above described, while in the 

 ovary or womb: some imperfect, which have them 

 not, till after they are excluded, as those of fishes, 

 which assume a white in the water. 



