FROM LAMARCK TO ST. HILAIRE 289 



environment in the elimination of species, groups, 

 and families, but does not assign this as a cause 

 of the origin of adaptations. Thus, many species 

 become extinct, while others become diminished 

 in numbers. Man himself exhibits the direct 

 modifying influence of his environment by wide 

 variations in his structure. The history of the 

 older geological periods is given us in the suc- 

 cession of fossils. Here Treviranus added to the 

 work of Cuvier the idea of progressive modifica- 

 tion in time, an idea which Cuvier never adopted. 

 Continuing to extend his evolution theory,^ we 

 find that he believed in abiogenesis, that every 

 form of life can be produced by physical forces 

 in one of two ways : either by coming into being 

 out of formless (inorganic) matter, or by the 

 modification of an already existing form by a 

 continued process of shaping. 



. . . Wherever Nature has exerted her building 

 forces she has brought forth Autochthones, living 

 bodies, 



. . . qui rupto robore nati. 

 Compositive luto, nullos liabuere parentes. 



Wherever like conditions prevailed, of climate, earth, 

 water, atmosphere, and a similar geographical posi- 

 tion, these Autochthones were similar, and the species 



^Biologic, oder PhUosophie der lebenden Natur, 1802, vol. Ill, 

 p. 224. 



