Professor Pictet on the Succession of Animals. 275 



not find among them any species actually living. Besides, 

 every time that one species is found in two different coun- 

 tries, the order of superposition in the formations proves that 

 it has lived there at the same epoch. To these arguments 

 many others might be added ; but they are sufficient to shew 

 the falsity of this theory, and we may now affirm that there 

 is no serious rivalry unless between the two others. 



Of the two theories now before us, the first explains the 

 succession of organized beings by the transformation of spe- 

 cies^ admitting that the animals of the ancient formations 

 have been modified by the influence of variations in the air, 

 temperature, &c., which have produced revolutions in the 

 globe ; that they insensibly undergo metamorphosis ; that 

 they have successively assumed the forms of which the 

 vestiges are preserved to us in the diff'erent strata or layers ; 

 and that from one change to another they have arrived at the 

 state which they exhibit in our days. 



The other theory admits a complete annihilation of species 

 by every catastrophe which has terminated an epoch, and a 

 new creation at the dawn of the following epoch. 



The theory of the transformation of species is to our mind 

 wholly inadmissible, and appears to us directly opposed to 

 all that we learn from zoology and physiology. This theory 

 is connected, as I have already intimated above, with the no- 

 tion of a scale of beings, and with that of gradual improve- 

 ment in the zoological ages ; it is their connecting tie, their 

 complement and explanation, and forms with them a complete 

 body of doctrine. Naturalists who have adopted one part of 

 these notions are naturally led to admit the others ; but the 

 same reasons which have induced us in the beginning of this 

 memoir to decline acknowledging, in a general and absolute 

 manner, a scale of beings, and the gradual improvement of 

 zoological faunas, likewise compel us to reject the idea of the 

 transformation of species as an explanation of the succession 

 of organized beings on the surface of the globe. 



It i^ necessary to observe, in the first place, that it is but 

 little probable that the forces of nature in the first ages of 

 the world were very different from what they are in our own 

 day. The same general laws which now regulate our globe 



