460 HISTORY OF PHYSIOLOGY. 



earliest antiquity of Greece ; for as we have al~ 

 ready said, the speculations of cosmogony were the 

 source of the Greek philosophy ; and the laws of 

 generation appeared to offer the best promise of 

 knowledge respecting the mystery of creation. Hip- 

 pocrates explained the production of a new animal 

 by the mixture of seed of the parents ; and the off- 

 spring was male or female as the seminal principle 

 of the father or of the mother was the more power- 

 ful. According to Aristotle, the mother supplied 

 the matter, and the father the form. Harvey's 

 doctrine was, that the ovary of the female is ferti- 

 lized by a seminal contagion produced by the seed 

 of the male. But an opinion which obtained far 

 more general reception was, that the embryo pre- 

 existed in the mother, before any union of the 

 sexes 11 . It is easy to see that this doctrine is 

 accompanied with great difficulties 12 ; for if the 

 mother, at the beginning of life, contain in her the 

 embryos of all her future children ; these embryos 

 again must contain the children which they are 

 capable of producing ; and so on indefinitely ; and 

 thus each female of each species contains in herself 

 the germs of infinite future generations. The per- 

 plexity which is involved in this notion of an end- 

 less series of creatures, thus encased one within the 

 other, has naturally driven inquirers to attempt other 

 suppositions. The microscopic researches of Leeu- 

 wenhoek and others led them to the belief that there 

 11 Bourdon, p. 204. I2 Ib. p. 209. 



