3IO ON NATURAL HISTORY, 



In fact, we have in the outward form abundant material for the 

 restoration of the internal organs. But how do we conclude, from 

 the peculiar many-ringed body, with jointed limbs, of this ancient 

 marine animal, that it had all these other peculiarities ; in short, that 

 it was a crustacean ? For any physiological necessity to the con- 

 trary, the creature might have had its mouth, nervous system, and 

 internal organs arranged like those of a fish. We know that it was 

 a crustacean and not a fish, simply because the observation of a vast 

 number of instances assures us that an external structure such as 

 this creature possesses, is invariably accompanied by the internal 

 peculiarities enumerated. Our method then is not the method of 

 adaptation, of necessary physiological correlations ; for of such ne- 

 cessities, in the case in question, we know nothing: but it is the 

 method of agreement ; that method by which, having observed 

 facts invariably occur together, we conclude they invariably have 

 done so, and invariably will do so ; a method used as much in the 

 common affairs of life as in philosophy. 



Multitudes of like instances could be adduced from the animal 

 world ; and if we turn to the botanist, and inquire how he restores 

 fossil plants from their fragments, he will say at once that he knows 

 nothing of physiological necessities and correlations. Give him a 

 fragment of wood, and he will unhesitatingly tell you what kind of a 

 plant it belonged to, but it will be fruitless to ask him what physio- 

 logical necessity combines, e.g. peculiarly dotted vessels, with fruit in 

 the shape of a cone and naked ovules, for he knows of none. Never- 

 theless, his restorations stand on the same logical basis as those of 

 the zoologist. 



Therefore, whatever Cuvier himself may say, or others may repeat, 

 it seems quite clear that the principle of his restorations was not that 

 of the physiological correlation or coadaptation of organs. And if it 

 were necessary to appeal to any authority, save facts and reason, our 

 first witness should be Cuvier himself, who, in a very remarkable 

 passage, two or three pages further on (Discours, pp. 184-185,1) 

 implicitly surrenders his own principle. 



Thus then natural history plainly teaches us that the utilitarian 

 principle, valuable enough in physiology, helps us no further, and is 

 utterly insufficient as an instrument of morphological research. 



But does she then tell us that in this, her grander sphere, the 

 human mind discovers no reflex, and that among those forms of being 

 which most approach himself alone, man can discover no indication 



^ Osseniens Fossiles, 4me edition, T. 1. 



