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mirable in that limitation ? For who informed thft 

 bird that she should lay eggs, arid want a nest to lodge 

 and nourish them with genial heat ? That this heat 

 would not be concentered round (he eggs, if the n -st 

 were too large, and that were it smaller it would not 

 be capable of containing all the young? Who has 

 taught her not to mis-calculate the time, or Jay her 

 eggs before she has completed her nest ? 



The same wisdom will more fully appear, if we ob- 

 serve what the egg contains, with the manner how the 

 young is there formed, and how it issues from its con- 

 finement. ^ 



The yolk lies in the heart of the egg, inclosed hi 

 the first membrane, which is surrounded by the se- 

 cond. Near the centre of the e**g are the ligaments 

 that sustain the yolk, which is contained in a peculiar 

 membrane. A second membrane incloses the first 

 white, a third and fourth encompasses the whole. Hie 

 shell is formed last of all out of the salts evacuated 

 from all the humours of the body, which the heat 

 gradually fixes and , consolidates, to serve a d nible 

 purpose, first that it may be excluded without crush- 

 tug the contents ; secondly, to defend their \ oir.ig, 

 till it is thoroughly formed, and ready to tort>aku the 



the membrane which surrounds th? yolk is a 

 white speck, which is the seed of the clii/.k iu minia- 

 ture. If the smallest portion of tlu vital spirit be in* 

 fused into it from the male, by a process of \v i.c'i we 

 have no idea, in the instant the chick receives life, arid 

 the whole substance is in motion. 1. it is not infused, 

 the egg may indeed be laid, but it never conies to a 

 living creature. 



The pulsation of the heart bears some analogy to 

 the pendulum of a clock, from whose vibrations the 

 whole machiuedcrivcs all its motions : the moment the 

 heart begins to beat, the animal is alive, and rect ives 

 by the umbilic duct, the nourishment which it traus- 



