AND HUMOURS. 555 



circumstances, (than within an animal), it is then denominated 

 an " egg," or "worm." I think, however, that in either case 

 the word "primordium" should be used to express that from 

 whence the animal is formed ; just as plants owe their origin 

 to seeds : all these " primordia" have one common property 

 that of vitality. 



I find a " primordium" of this kind in the uterus of all 

 viviparous animals before any trace of a foetus appears : there 

 is a clear, thick, white fluid (like the albumen of the egg) 

 inclosed in a membrane, and this I call the ovum. In the 

 roe, fallow-deer, sheep, and other cloven-footed animals, it fills 

 the whole uterus and both its horns. 



In process of time an extremely limpid and pure watery fluid 

 (similar to that which in the hen's egg I have called the col- 

 liquament) is secreted by this " primordium" or "ovum;" 

 in clearness and brilliancy far exceeding the remaining fluid of 

 the ovum in which it is contained. It is of a circular form, 

 and inclosed in a very delicate and transparent membrane of 

 its own called the " amnion." The other fluid, of a denser and 

 thicker character, is contained in the outer envelope, or chorion, 

 which is in immediate contact with the concave surface of the 

 uterus, and which also encompasses the entire ovum : the shape 

 of this second membrane varies according to that of the uterus : 

 in some animals it is oval, in others oblong, but in those with 

 cloven feet it resembles a saddle-bag. After a short time 

 a red pulsating point shows itself within the transparent 

 substance, and from this point exceedingly fine twigs, or rather 

 rays of vessels, start forth. By and by the first aggregated 

 portion of the body makes its appearance, folded upon it- 

 self orbicularly, and somewhat resembling a grub : the re- 

 maining parts follow in the order described in our history. 

 For I have ascertained that the production of the foetus from 

 their ova or " conceptions" in viviparous animals, takes place 

 exactly in the same way as the growth of the chick within 

 the egg. 



As I before observed, "conceptions" in viviparous animals 

 vary in form, number, and in their modes of attachment to 

 the uterus. At first, especially in the cloven-footed animals, 

 the "conception" does not adhere to the uterus, but is only in 

 contact with, and fills and distends the organ, and can be easily 



