234 ON GENERATION. 



Aristotle 1 appears to have known this dissolved fluid, when 

 he says : " A membrane, too, marked with sanguineous fibres, 

 surrounds the white fluid at this time (the third day), arising 

 from those orifices of the veins." Now the philosopher can 

 neither be supposed by the words " white fluid," to refer to 

 the albumen at large, because at this period the membrane of 

 the white is not yet covered with veins; it is only the membrane 

 of the dissolved fluid which appears with a few branches of 

 veins distributed over it here and there. And because he says : 

 "this membrane, too," as if he understood another than those 

 which he had spoken of as investing the albumen and the yelk 

 before incubation, and designated this one as first arising after 

 the third day, and from the orifices of the veins. 



Goiter seems also to have known of this dissolved fluid ; he 

 says : " A certain portion of the albumen acquiring a white 

 colour, another becoming thicker." The fluid in question is 

 surrounded with its proper membrane, and is distinct and 

 separate from the rest of the albumen before there is any 

 appearance of blood. We shall have occasion, by and by, to 

 speak of the singular importance of this fluid to the foetuses of 

 every animal. Whilst they float in it they are safe from suc- 

 cussion and contusion, and other external injury of every kind; 

 and they moreover are nourished by it. I once showed to 

 their serene majesties the king and queen, an embryo, the size 

 of a French-bean, which had been taken from the uterus of 

 a doe ; all its membranes were entire, and from its genital 

 organs we could readily tell that it was a male. It was, in 

 truth, a most agreeable natural spectacle ; the embryo perfect 

 and elegant, floating in this pure, transparent, and crystalline 

 fluid, invested with its pellucid tunica propria, as if in a glass 

 vessel of the greatest purity, of the size of a pigeon's egg. 



EXERCISE THE SEVENTEENTH. 



The third inspection of the egg. 



Having seen the second process or preparation of the egg, 

 towards the production of the embryo which presents itself in 

 1 Hist. Anim. lib. vi, cap. 3. 



