and a ray of light has lately sprung which has grealrV 

 brightened the shades in which the mystery of genera- 

 tion is yet involved. 



Bestow your whole attention on ~this, you will tliea 

 discover an important truth-. A' membrane clothes the " 

 inside of the yoik of an egg ; and this membrane, which " 

 is only a continuation of that which clothes the slender 

 intestine of tne chick, is coinwoir to the stomach, 

 pharynx, mouth, skin, and epidermis/ Another mem- 

 brane enfolds the yolk externally, and this -membrane ' 

 is only a continuation of that which covers the intestine, 

 it unites wil*Vthe' mesentery and peritoneum. The ar- 

 teries and -veins that gently move in the. eg<r, derive 

 their origin from the mesenteric arteries and veins of 

 the embryo. The bldod which- circulates in the 

 yolk receives the principle of its motion from the 

 heart, 



The. yoik then is essentially a dependance of the in- 

 testines of the embryo, and together with that composes < 

 one and the same organized whole ; so that at its pri- - 

 mary period, it is in some measure an animal with two 

 bodies : the head, trunk; and extremities compose one 

 of these bodies; the intestines and yolk -the other. At 

 the end of the incubation the second body connects - 

 \vjth the first, .and both toge4her form only one. 



But since the yolk .exists in eggs that have not been 

 fecundated, it necessarily follows that the germ existed 

 before fecundation. This consequence is self-evident : 

 you have lately seen thai the yolk is an -essential part of 

 the chick ; you have observed the strict communication * 

 between them. The chick then has never existed with- - 

 cut it. The membranes and vessels of the former are 

 only a continuation of the membranes and vessels of 

 the latter. And what a number of other things are 

 there which are common to both, and which prove tlmt 

 they have never existed separately ! The chick was then > 

 entire in the egg before fecundation. It does not, there- 

 fore, owe its origin to the liquor furnished by the cock, 

 but was stretched in minature in the egg previous to it. 

 Coastquently, the germ belongs solely to the female. 



