3o8 ON NATURAL HISTORY, 



it to be supposed then that Cuvier did not himself understand the 

 methods by which he arrived at his great results ? that his master- 

 mind misconceived its own processes ? This conclusion appears to be 

 not a little presumptuous ; but if the following arguments be justly 

 reasoned out, it is correct. 



In the famous " Discours sur les Revolutions de la Surface du 

 Globe,'' after speaking of the difficulties in the way of the restoration 

 of vertebrate fossils, Cuvier goes on to say — 



" Happily, comparative anatomy possesses a principle whose just 

 development is sufficient to dissipate all difficulties ; it is that of the 

 correlation of forms in organized beings, by means of which every 

 kind of organized being might, strictly speaking, be recognised by a 

 fragment of any of its parts. 



" Every organized being constitutes a whole, a single and complete 

 system, whose parts mutually correspond, and concur, by their 

 reciprocal reaction, to the same definite end. None of these parts 

 can be changed without affecting the others ; and consequently, each 

 taken separately indicates and gives all the rest." 



After this Cuvier gives his well-known examples of the correlation 

 of the parts of a carnivore, too long for extract ; and of which there- 

 fore his summation merely will be given : — 



" In a word, the form of the tooth involves that of the condyle ; 

 that of the shoulder blade ; that of the claws : just as the equation of 

 a curve involves all its properties. And just as by taking each pro- 

 perty separately and making it the base of a separate equation, we 

 should obtain both the ordinary equation, and all other properties 

 whatsoever which it possesses ; so, in the same way, the claw, the 

 scapula, the condyle, the femur, and all the other bones taken 

 separately will give the tooth, or one another ; and by commencing 

 with any one, he who had a rational conception of the laws of the 

 organic economy, could reconstruct the whole animal." 



Thus far Cuvier : and thus far and no further, it seems that the 

 compilers, and copyers, and popularizers, and id genus omne, proceed 

 in the study of him. And so it is handed down from book to book, 

 that all Cuvier's restorations of extinct animals were affected by 

 means of the principle of the physiological correlation of organs. 



Now let us examine this principle ; taking in the first place, one 

 of Cuvier's own arguments and analyzing it ; and in the second place, 

 bringing other considerations to bear. 



Cuvier says — " It is readily intelligible that ungulate animals 

 must all be herbivorous, since they possess no means of seizing a 

 prey (i). We see very easily also, that the only use of their fore feet 



