438 ON THE METHOD OF PALAEONTOLOGY 



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

 taken separately indicates and gives all the rest." 



The first paragraph here embodies the principles of both physio- 

 logical and morphological correlation. The second paragraph, how- 

 ever, regards physiological correlation only, and the statement which 

 it contains is not true. We have no evidence to justify us in asserting 

 that no one part can be changed without affecting all the others. On 

 the contrary, we have abundant evidence to show that allied species, 

 for instance, differ in only a single character ; which would be an 

 impossibility if a change in one part sensibly affected all the rest. 



Cuvier then goes on to show, in a very beautiful manner, the 

 physiological correlation which exists between the parts of a 

 Carnivore, concluding with the well-known phrase, " 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 coni- 

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

 of the organic oeconomy could reconstruct the whole animal" 



If Cuvier means by "the laws of the organic ceconomy,'' (and 

 the context would indicate that he does,) its physiological laws 

 merely, then I must venture to say, that I believe this assertion to be 

 incorrect. I do not believe that the problem — given a tooth or a 

 bone, the mode of life of an animal, and the laws of physiology, to 

 find the structure of other parts of the body of that animal, — is a 

 soluble one. 



In fact, Cuvier himself, in the very next paragraph (p. 182), almost 

 gives up his own principle. I give his own words : — 



" Ce principe est assez evident en lui-meme dans cette acceptation 

 generate pour n'avoir pas besoin d'une plus ample demonstration ; 

 7nais quand il s'agit de I'appliqiier, il est mi grand nombre de cas oil 

 notre connaissance theoriqiie des rapports des formes ne suffirait point si 

 elle n'etait appuyee siir V observation!^ 



And again, in concluding, at p. 187 Cuvier says : — 



" Et, en adoptant ainsi la nie'tlwde de F observation connne un inoyen 

 supplementaire quand la tli(-orie nous abandonne, on arrive a des details 

 faits pour etonner. La moindre facette d'os, la moindre apophyse, 

 ont un caractere determine relatif a la classe, a I'ordre, au genre 

 et a I'espece auxquels elles appartiennent, au point que toutes les fois 

 que Ton a seulement une extremite d'os bien conservee on peut avec 

 de I'application, et en s'aidant avec un peu d'adresse de I'analogie 

 et de la comparaison effective, determiner toutes ces choses aussi 

 siirement que si Ton possedait I'animal entier." 



Finally, at page 184, after speaking of those invariably coexistent 



