ON GENEEATION. 419 



But as soon as the sternum is fashioned the heart enters into 

 the chest as into a dwelling which it had built and arranged 

 for itself; and there, like the tutelary genius, it enters on the 

 government of the surrounding mansion, which it inhabits with 

 its ministering servants the lungs. The liver and stomach are 

 by and by included within the hypochondria, and the intestines 

 are finally surrounded by the abdominal parietes. And this is 

 the reason wherefore without dissection the heart can no longer 

 be seen pulsating in the hen's egg after the tenth day of incu- 

 bation. 



About this epoch the point of the beak and the nails appear of 

 a fine white colour ; a quantity of chylous matter presents itself 

 in the stomach ; a little excrement is also observed in the in- 

 testine, and the liver being now begun, some greenish bile is 

 perceived ; facts from which it clearly appears that there is 

 another digestion and preparation of nutriment going on be- 

 sides that which takes place by the branches of the umbilical 

 veins ; and it is reasonable matter of doubt how the bile, the 

 excrementitious matter of the second digestion, can be separated 

 by the instrumentality of the liver from the other humours, 

 when we see it produced at the same time as this organ. 



In the order now indicated are the internal organs generated 

 universally ; in all the animals which I have dissected, particu- 

 larly the more perfect ones, and man himself, I have found 

 them produced in the same manner : in these, in the course of 

 the second, third, and fourth month, the heart, liver, lungs, 

 kidneys, spleen, and intestines present themselves inchoate and 

 increasing, and all alike of the same white colour which belongs 

 to the body at large. Wherefore these early days are not im- 

 properly spoken of as the days when the embryo is in the 

 milk ; for with the exception of the veins, particularly those of 

 the umbilicus, everything is as it were spermatic in appearance. 



I am of opinion that the umbilical arteries arise after the 

 veins of the same name, because the arteries are scarcely to be 

 discovered in the course of the first month, and take their rise 

 from the branches that descend to either lower extremity. I do 

 not believe, therefore, that they exist until that part of the body 

 whence they proceed is formed. The umbilical veins, on the 

 contrary, are conspicuous long before any part of the body is 

 begun. 



