GREEK BIOLOGY AND MEDICINE blood in the white of the egg. This point beats and moves as though endowed with Kfe, and from it two vein-ducts with blood in them trend in a convoluted course; and a membrane carrying bloody fibres now envelops the yolk, leading off from the vein-ducts. A Httle after- wards the body is differentiated, at first very small and white. The head is clearly distin- guished, and in it the eyes, swollen out to a great extent, . . ." ^^ Without carrying further our citation on the chick, we may remark that Aristotle saw all that can be seen without a microscope. His description of the gestation of the placental sharks makes too difficult a matter for a lay- man to set forth for other laymen. I will borrow the account given by an Aristotelian scholar who is himself a biologist. " There is perhaps no chapter in the His- toria Animalmm more attractive to the anato- mist than one which deals with the anatomy and mode of reproduction of the cartilaginous fishes, the sharks and rays, a chapter which moved to admiration that prince of anatomists, Johannes Miiller. The latter wrote a volume [Ueber den glatten Hai des Aristoteles, Berlin, 1842] on the text of a page of Aristotle, a page
[56]
[56]
