THE TRANSMUTATION OF SPECIES. 



LAMARCK. 



UP to the middle of the present century, naturalists in 

 general had regarded 'species,' both of animals and 

 plants, as immutable entities, founded upon abstract 

 conceptions in the mind of a Creative Being, and 

 necessarily incapable of modification except within the 

 narrowest limits. It was held that each species had 

 been created with a determinate and invariable organisa- 

 tion, by which it was specially adapted to the particular 

 region which it inhabited. On this view, the habits of 

 the species were the necessary result of its organisation, 

 and as the latter was believed not to vary, so it was 

 assumed that the former were also invariable. We have 

 seen that Edward Forbes held this opinion, and that 

 it was to the same doctrine that Cuvier lent the support 

 of his immense influence and his vast learning. 



At the present day, it is questionable if there exist 

 any naturalists who regard ' species ' as being independent 

 creations, in the sense in which Cuvier and Edward 

 Forbes held that they were. The principle of evolution, 



