EIGHTEENTH CENTURY EVOLUTIONISTS 161 



of date or upon the side tracks of thought. They 

 can be sharply distinguished from both the 

 naturahsts and natural philosophers of the eigh- 

 teenth century in the fact that their speculations 

 advanced \v itiiout the least support of observa- 

 tion and without the least deference to inductive 

 canons. Several of them were very popular 

 writers, and unchecked speculation was so much 

 their characteristic that they undoubtedly re- 

 tarded the development of the true evolution 

 idea by drawing ridicule upon all genuine search 

 for a naturalistic explanation of the phenomena 

 of life. 



We find them reviving Greek ideas as to abio- 

 genesis or the spontaneous origin of life in dif- 

 ferent forms, as well as in metamorphoses and 

 transformations, hardly less sudden and fantas- 

 tic than those of Empedocles. Another source of 

 their authority is the highly imaginative natural 

 history hteratuie of the Middle Ages. In all this 

 chaff there is of course some wheat, as is some- 

 times the case in speculation unhindered by ob- 

 servation. Lines of suggestion coming near to 

 modern thought upon heredity are found espe- 

 cially in. the essays of Maupertuis, who drew 

 from Democritus and Anaxagoras. De Maillet 

 outlined a theory of 'transmission of acquired 

 characters' in a crude form similar to that of 

 Empedocles' suggestion regarding the origin of 



