HISTORICAL SKETCH. xxiil 



remarkable skill and force. He argues from the analogy 

 of domestic productions, from the changes which the 

 embryos of many species undergo, from the difficulty 

 of distinguishing species and varieties, and from the 

 principle of general gradation, that species have been 

 modified; and he attributes the modification to the 

 change of circumstances. The author (1855) has also 

 treated Psychology on the principle of the necessary 

 acquirement of each mental power and capacity by 

 gradation. 



In 1852 M. JSTaudin, a distinguished botanist, ex- 

 pressly stated, in an admirable paper on the Origin of 

 Species (' Eevue Horticole,' p. 102 ; since partly repub- 

 lished in the ' Nouvelles Archives du Museum,' torn. i. 

 p. 171), his belief that species are formed in an 

 analogous manner as varieties are under cultivation ; 

 and the latter process he attributes to man's power of 

 selection. But he does not show how selection acts 

 under nature. He believes, like Dean Herbert, that 

 species, when nascent, were more plastic than at 

 present. He lays weight on what he calls the principle 

 of finality, " puissance mysterieuse, indeterminee ; 

 fatalite pour les uns ; pour les autres, volonte provi- 

 dentielle, dont Taction incessante sur les etres vivants 

 determine, a toutes les epoques de l'existence du monde, 

 la forme, le volume, et la duree de chacun d'eux, en 

 raison de sa destinee dans l'ordre de choses dont il fait 

 partie. C'est cette puissance qui harmonise chaque 

 membre a 1' ensemble, en l'appropriant a la fonction qu'il 

 doit remplir dans l'organisme general de la nature, 

 fonction qui est pour lui sa raison d'etre." * 



* From references in Bronn's ' Untersuchungen liber die Ent- 

 wickelungs-Gesetze,' it appears that the celebrated botanist 



