HISTORICAL SKETCH. 



Zoolog.,' Jan. 1851), briefly gives his reason for believing that 

 specific characters " sont fixes, pour chaque espece, tant qu'clle se 

 perpetue au milieu des mSmes circonstances : ils se modifient, si 

 les circonstances ambiantes viennent a changer." " En resume', 

 I 'observation des animaux sauvages ddmontre deja la variabilitc 

 limitee des especes. Les experiences sur les animaux sauvages 

 devenus doinestiques, et sur les animaux domestiqucs redevenus 

 sauvages, la de'montrent plus clairement encore. Ces memes expe- 

 riences prouvent, de plus, que les differences produites peuvent etro 

 de valeur gene'rique." In his ' Hist. Nat. Ge'nerale ' (torn. ii. p. 

 430, 1859) he amplifies analogous conclusions. 



From a circular lately issued it appears that Dr. Freke, in 1851 

 (' Dublin Medical Press,' p. 322), propounded the doctrine that all 

 organic beings have descended from one primordial form. His 

 grounds of belief and treatment of the subject are wholly different 

 from mine ; but as Dr. Freke has now (1861) published his Essay 

 on ' the Origin of Species by means of Organic A ffinity,' the diffi- 

 cult attempt to give any idea of his views would be superfluous 

 on my part. 



Mr. Herbert Spencer, in an Essay (originally published in the 

 ' Leader,' March 1852, and republished in his ' Essays ' in 1858), 

 has contrasted the theories of the Creation and the Development 

 of organic beings with 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 dis- 

 tinguishing 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. Naudin, a distinguished botanist, expressly stated, 

 in an admirable paper on the Origin of Species (' Eevue Horticole, 

 p. 102 ; since partly republished 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 myst^rieuse, inde'terminee ; fatalite pour les uns ; pour 

 les autres, volont^ providentielle, dont Taction incessante sur les 

 gtres vivants determine, a toutes les 6poques de l'existence du 

 monde, la forme, le volume, et la dur<Se de chacun d'eux, en raison 



