GENEOLOGICAL. 367 



nings of embryological observation in the seven- 

 teenth century, there was little progress for another 

 hundred years. For the eighteenth century embry- 

 ologists, if so they may be called, gave more atten- 

 tion to arguments over general conceptions than to 

 the accumulation of facts. 



In the early part of the eighteenth century, the 

 embryological observations of investigators, like 

 Boerhaave and Malpighi, were summed up in the 

 conception that development was merely an expan- 

 sion or unfolding of a pre-existent or preformed 

 rudiment within the efi;^. 



This preformation theory, which found more and 

 more definite expression in the works of Bonnet, 

 Buifon, and others, may be thus summed up: — * 



The germ, whether egg-cell or seed, was believed 

 to be a miniature model of the adult. " Pre- 

 formed " in all transparency the organism lay 

 within the egg, only requiring to be unfolded. In 

 contrast to Harvey's conclusion : " the first concre- 

 ment of the future body grows, gradually divides, 

 and is distinguished into parts; not all at once, but 

 some produced after the others, each emerging in its 

 order," was Haller's first and last utterance, " There 

 is no becoming; no part of the body is made from 

 another, all are created at once,'' or Bonnet's " fun- 

 damental principle, that nothing is generated, and 

 that what we call generation is but the simple de- 

 velopment of what pre-existed under an invisible 

 form, and more or less different from that which 

 becomes manifest to our senses." 



But this was not all. The germ was more than a 



* Soe Geddes and Thomson, The Evolution of Sex, 4th 

 ed., 1901, p. 90. 



