36 FROM THE GREEKS TO DARWIN 



ture, and that development consisted merely in 

 the enlargement of this miniature. This doctrine 

 of 'emboitemenf of Bonnet, defended by Swam- 

 merdam, Haller, Reaumur, and Cuvier, like the 

 doctrine of abiogenesis, long stood in the way 

 of the progress of the evolution idea; for if it 

 were true that all beings had been preformed 

 from the beginning, there could naturally be no 

 evolution of form, nor any necessity for a the- 

 ory of Evolution. Long before Aristotle, the 

 principle of syngenesis, or formation of the em- 

 bryo by the union of elements from both parents, 

 was rightly understood by Empedocles. The no- 

 tion of hereditary transmission of characters was 

 extremely ancient, and was naturally founded 

 upon the early observed likeness of offspring to 

 parents. Aristotle also commented upon the prin- 

 ciples of the prepotency of the characteristics of 

 one parent over the other, as well as of atavism. 

 The growth of embryology as an objective 

 science came, of course, with the invention of 

 microscopic lenses. Degraff, in the discovery of 

 the ovum in 1678, Leeuwenhoek (1632-1723), 

 in the discovery of the spermatozoon, laid the 

 foundations of the science which Meckel, in 1813, 

 and von Baer, in 1827, built into one of the key- 

 stones of Evolution. Von Baer's law, that higher 

 animals passed through embryonic stages in 

 which they resemble the adult forms of lower 



