EVOLUTION OF THE CHICK. 173 



the eggs abortive : arid there is scarcely an instance of 

 a hatch of eggs that will not afford a greater number 

 of chickens, if a little artificial assistance be afforded. 

 Some of the chicks, for instance, are weak ; while 

 others, though not wanting in strength, still meet 

 with more resistance than they can overcome from 

 the shell or its membrane ; and others again, though 

 sufficiently strong, and enclosed in a shell and mem- 

 brane of the usual thickness and consistence, are 

 unable to effect an exit, even when an aperture is 

 made for them, in consequence, it would appear, of 

 some unknown cause depriving them of the power of 

 making the circular revolution on their own bodies, 

 which, remaining in the same position, stick to the 

 shell. 



In order to understand how a chick may be thus 

 glued to its shell it will be necessary to recollect, 

 that between its body and the lining membrane is 

 the white of the egg, or glairy adhesive fluid, which, 

 by drying, becomes a sort of cement, very apt to 

 cause the feathers to adhere to the membrane with 

 wliich they are in contact. The chick of an egg 

 which has been subjected in artificial hatching to a 

 temperature too high is in the most danger of such an 

 accident ; though it seldom happens before it has 

 made a pretty large breach in the place first chipt, 

 and has also rent the membrane, after which opera- 

 tions it remains a good while at rest. The air intro- 

 duced through this rent soon changes into a hard 

 tenacious glue the fluid white next the margin of the 

 aperture, as well as to some distance inward ; so that 

 when the chick is desirous of returning to its task it 

 can only peck at the same place, being held fast from 

 moving its body by the glue. Its attempts pull the 

 feathers, and make it squeak; and from its efforts being 

 more and more painful, the desire to move is aban- 

 doned. Under such circumstances the chick, if un- 



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