120 SPECIES. 



that some neighbouring animal species are derived from a 

 given prototype, similar to themselves, and without any ante- 

 cedents in the organic world ? This is to return to Cuvier ! 

 Limited ! Does he mean that the modifications will not be 

 considerable in the present state of things, on account of this 

 present state being more or less modified ? It comes to nothing 

 directly we admit variety as a consequence of the medium. 

 Etienne Geoffroy was led by this kind of idea, when, limiting 

 his view to the short period of historical time, and thinking 

 he had discovered that our present climates do not sensibly alter 

 existing species,* he asked, "if there had not been on the 

 earth revolutions and disturbances of so vast a character that 

 their influence may not have been enormous ; whilst in our 

 days, changes may have been according to the power of their 

 effects, that is to say, almost nothing." And he explained 

 everything by this convenient theory of geological floods. 



Before going farther, let us consider what we ought to think 

 about the disturbances of the terrestrial globe thus invoked by 

 Etienne Geoffroy. Now, to our mind, we have no authentic 

 proof that the past of our planet has really been marked by 

 such frightful revolutions, and geology does not make the 

 tradition as clear as some have desired. We think, although 

 this is not the place to prove it, that if the changes which have 

 happened to the surface of the globe have been considerable, 

 they ought to be proportionally weak, resulting less from sud- 

 den and powerful efforts than from those small and continuous 

 actions f in which nature puts forth its most formidable ener- 

 gies, but the progress of which is not to be measured by the 

 memory of man. In general, our mind seizes but badly the 

 notion of duration beyond certain limits. It is not the same 

 with the notion of force. Hence, the belief in floods. In the 

 presence of gigantic effects, the mind, in the appreciation of 

 the movers of this effect, has done what we have done every 



* " The observation of species in a state of nature, by revealing to us a 

 multitude of modifications more or less important, cannot show us any se- 

 rious deviation from the types formed or preserved by the influence of the 

 existing state of things." Isidore Geoffrey, Vie d'Etienne Geoffroy, p. 349. 



f See Leibnitz, Protog^e, transl. by Bertrand de Saint-Germain, Introduc- 

 tion, p. 61. 



