96 OF REPRODUCTION. 



to present itself under the appearance of a vesicle, known by the 

 name of ovule. In ireptiles and birds the ovule is very large, com- 

 paratively to that of women; in all the mammiferae its reproduction 

 is extremely simple: the ovary is a gland whose special function it 

 is to secrete ovules, as the liver secretes bile, &c. MM. Prevost 

 and Dumas assure us that they have proved that the ovules are really 

 formed by the ovary, and by nothing but the ovary; that they always 

 exist in this gland, in adult females, who are capable of fecundation; 

 that they are not developed until puberty, and are not found in old 

 age; that animals that copulate at all seasons of the year also have 

 them without interruption until they become sterile, while on the 

 other hand they are only met with at the season of copulation in 

 those animals that have only one rutting time in each year. 



240. These vesicles, at first very small, grow at last to the size of 

 a hempseed. As in fowls, they do not all grow at the same time; 

 one or two generally exceeding the rest, and reaching the state of 

 maturity first. Their coats are then thick and opake, rise more or less 

 above the surface of the ovary, and seem as if they would burst its 

 investinor membrane. At this period of its evolution the germ is 

 composed of two small coats, one external, the largest adheres to 

 the tissue of the ovary; the other, internal, smaller, really constitutes 

 the ovule, while MM. Prevost and Dumas propose to restrict the 

 name of vesicle to the former. 



241. After the discovery of the ovules, and particularly during the 

 last century, philosophers were desirous to know whether they are 

 transmitted from the mother to the daughter, together with the prin- 

 ciples of her organs; or whether, on the other hand, they are not 

 formed until the age of puberty. This question, which gave rise 

 to the celebrated theory of the encasmg" of germs one within another, 

 has been especially argued by Swammerdam, Haller and Bonnet. 

 The latter insisted with great zeal, that we ought to carry back the 

 orio-in of the human beings that now cover, have covered, or will 

 hereafter cover the globe in all succeeding ages, to the ovary of the 

 first woman; that is to say, that the ovaries of the first woman must 

 have enclosed, shut up one within another, the germs of all the ge- 

 nerations that have succeeded, or will hereafter succeed; in a word, 

 the whole human race. But these infinite divisions, in which the 

 imagination loses itself, have caused the idea of the pre-existence of 

 germs to be rejected, and at the present day they are regarded as the 

 results of a mere secretion. 



§. II. Ol* tiie male Germ. 



242. The germ furnished by male animals, is a whitish, viscid 



