FROM THALES TO LUCRETIUS. 2 l 



vision, is his anticipation of what is known as Epi- 

 genesis, or the theory of the development of the 

 germ into the adult form among the higher indi- 

 viduals through the union of the fertilizing powers 

 of the male and female organs. This theory, which 

 was proved by the researches of Harvey, the dis- 

 coverer of the circulation of the blood, and is ac- 

 cepted by all biologists to-day, was opposed by Mal- 

 pighi, an Italian physician, born in 1628, the year 

 in which Harvey published his great discovery, and 

 by other prominent men of science down to the last 

 century. Malpighi and his school contended that 

 the perfect animal is already " preformed " in the 

 germ; for example, the hen's egg, before fecunda- 

 tion, containing an excessively minute, but com- 

 plete, chick. It therefore followed that in any germ 

 the germs of all subsequent offspring must be con- 

 tained, and in the application of this "box-within- 

 box " theory its defenders even computed the num- 

 ber of human germs concentrated in the ovary of 

 mother Eve, estimating these at two hundred thou- 

 sand millions! 



When the " preformation " theory was revived by 

 Bonnet and others in the eighteenth century, Eras- 

 mus Darwin, grandfather of Charles Darwin, passed 

 the following shrewd criticism on it : " Many in- 

 genious philosophers have found so great difficulty 

 in conceiving the manner of reproduction in animals 

 that they have supposed all the numerous progeny 

 to have existed in miniature in the animal originally 



