l66 EVOLUTION, OLD AND NEW. 



have, as we have said, experienced in a perceptible 

 manner all the eflfects of different causes of degenera- 

 tion. Only it shonld be lemarted in regard to these 

 greater species, such as the elephant and hippopotamus, 

 that in comparing their fossil remains with the existing 

 forms we find the earlier ones to have been larger. 

 Nature was then in the full vigour of her youth, and 

 the interior heat of the earth gave to her productions 

 all the force and all the extent of which they were 

 capable .... if there have been lost species, that is 

 to say animals which existed once, but no longer do so, 

 these can only have been animals which required a 

 heat greater than that of our presen,t torrid zone." * 



The context proves Buffon to have been thinking of 

 such huge creatures as the megatherium and mastodon, 

 but his words seem to limit the extinction of species 

 to the denizens of a hot climate which had turned 

 colder. It is not at all likely that Buffon meant this, 

 as the passage quoted at p. 146 of this work will suffice 

 to show. The whole paragraph is ironical. 



I can see nothing to justify the conclusion drawn 

 from this passage by Isidore Geofifroy, that Buffon 

 had modified his opinions, and was inclined to believe 

 in a more limited mutability than he had done a few 

 years earlier. His exoteric position is still identical 

 with what^ it was in the outset, and his esoteric may be 

 seen from the spirit which is hardly concealed under the 

 following : — 



"I shall be' told that analogy points towards the 

 belief tliat our own race has followed the same path, 

 * ' Hist. Nat.,' Sup. torn. v. p. 27, 1778. 



