FROM LAMARCK TO ST. HILAIRE 297 



plan, but of a common parentage. From common 

 sources existing species have issued through long 

 intermediate series, and the sum of their analo- 

 gies and differences represents their greater or 

 less remoteness from each other and from the 

 common source. From relatively few primordial 

 types Nature has given birth to all the organ- 

 isms which people the globe. He quite literally 

 follows Lamarck's conception of filiation as a 

 branching system, but he widely departs from 

 Lamarck as to the causes of Evolution. With 

 Goethe he sees in living organisms a 'plasticity,^ 

 which renders them susceptible to direct modifi- 

 cation by environment and opposes the conser- 

 vative power of atavism, or hereditary transmis- 

 sion of type. As with Bory de St. Vincent, he 

 believes that the younger primitive types pre- 

 sented greater 'plasticity,' but that with advanc- 

 ing ages the forces of heredity accumulated and 

 became stronger. 



Behind that 'plasticity' and 'atavism,' how- 

 ever, Naudin, somewhat after the Aristotelian 

 conception of the creation of form in matter, 

 places a higher power — 'Finality' — a mysterious 

 force, which, he says, some would call 'fatality' 

 and others 'providence,' the continuous action of 

 which upon beings determines the form, size, 

 and duration of each species in relation to the 

 order of things of which it forms a part. The 



