110 HABITS OF BIRDS. 



maining portion, it receives the hard covering of tne 

 shell, previous to its exclusion. 



New-laid Egg with part of the Shell removed. 



It will hence he manifest that, reckoning from the 

 shell inwards, there are six different envelopes, one 

 only of which could be detected before the descent 

 of the egg into the egg-tube. 1. The shell ; 2. the 

 external layer of the membrane of the shell ; 3. the 

 internal layer ; 4. the white ; 5. the chalaziferous 

 membrane ; 6. the proper membrane. 



Harvey was the first who demonstrated two sepa- 

 rate whites in an egg, each enveloped in its proper 

 membrane, " the one/' he tells us, "* thinner and more 

 liquid, the other thicker and more clammy, and a 

 little more inclining to whiteness, in staler eggs, 

 after some days* incubation, growing yellowish. As 

 this second white covers the yolk round, so the 

 exterior liquor encompasses iU That these two 



