20 HISTORICAL SKETCH 



torical sketch, were long ago preceded by Dr. Wells and 

 Mr. Matthews. 



M. Isidore Geoffroy Saint-Hilaire, in his lectures de- 

 livered in 1850 (of which a R<^sum^ appeared in the 

 "Revue et Mug. de Zoolog.," Jan. 1851), briefly gives 

 his reason for believing that specific characters "sont 

 fixes, pour chaque esp^ce, tant qu'elle se perpdtue au 

 milieu des memes circonstances: ils se modifient, si les 

 circonstances ambiantes viennent a changer." "En r^- 

 suni^, I' observation des animaux sauvages d^montre dej^ 

 la variabilite liinitee des esp^ces. Les experiences sur les 

 animaux sauvages devenus domestiques, et sur les ani- 

 maux domestiques redevenus sauvages, la d^montrent 

 plus clairement encore. Ces memes experiences prou- 

 vent, de plus, que les differences produit'es peuvent etre 

 de valeur generique.'' In his "Hist. Nat. Generale" (torn, 

 ii., page 430, 1859) he amplifies analogous conclusions. 



From a circular lately issued it appears that Dr. 

 Freke, in 1851 ("Dublin Medical Press," page 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 Or- 

 ganic Affinity," the difficult attempt to give any idea 

 of his views would be superfluous on my part. 



Mr. Herbert Spencer, in an Essay (originally pub- 

 lished 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 em- 



