312 OF THE GROWTH, &c. 



were too great; for the degress of heat neceflary 

 for hatching eggs are very limited ; and the 

 leaf! excefs or defed^ is eqiiaHy fatal to this ope- 

 ration. The ]ii\ eggs, therefore, laid by the 

 hen, containing the embryos in the fame lUt^ 

 as the hrll:, prove nothing more than the neceffi- 

 ty of their acquiring full perfection before they 

 can be hatched. 



It is apparent, therefore, that tlie ftate of the 

 embryo when the egg is laid by the hen, is its 

 firft ftate, and that which immediately fuccceds 

 impregnation ; that it undergoes no interme- 

 diate changes of form ; and, confequently, by 

 tracing, as Malpighius has done, its gradual ex- 

 panfion, hour after hour, we difcover every 

 thing that it is pofTible for us to know, unlefs 

 %ve could perceive the mixture of the two fluids, 

 and the manner in which the particles arrange 

 themfelves during the firft formation of the em- 

 bryo. 



If v.^e renefl on this inftantanepus fecundation 

 of a number of eggs, which are to be laid at fuc- 

 'cefTive intervals, w^e fliall difcover a new^ argu- 

 ment againfc the exiftence of eggs in viviparous 

 animals : For, if \vomen contained eggs, like 

 hens, why are not many of them fecundated at 

 the fame time ? Why does not one impregnation 

 give birth to a fucceftive race of children ? And, 

 when women conceive two or three children, 

 why do they always come into the world at the 

 fame time ? If thefe foetufes were produced from 



eggs. 



