THE SURFACE OF THE GLOBE. 61 



Principle of this determination. 



Fortunately, comparative anatomy possesses a principle which, pro- 

 perly developed, was capable of clearing up all embarrassment : it was 

 that of the natural relation of forms in organized beings, by means of 

 which each sort of creature may, by rigorous scrutiny, be known by 

 each fragmant of each of its parts. 



Every organized being forms a whole, an unique, and perfect system, 

 the parts of which mutually correspond, and concur in the same definitive 

 action by a reciprocal re-action. None of these parts can change with- 

 out the whole changing ; and consequently each of them, separately 

 considered, points out and marks all the others. 



Thus, as I have before remarked, if the intestines of an animal are 

 so organized as only to digest flesh, and that fresh, it follows that its 

 jaws must be constructed to devour a prey, its claws to seize and tear 

 it, its teeth to cut and divide it, the whole structure of its organs of 

 motion such as to pursue and catch it, its perceptive organs to discern it 

 at a distance ; nature must even have placed in its brain the necessary 

 instinct, to know how to conceal itself and lay snares for its victims. 

 Such will be the general conditions of the carnivorous kingdom ; every 

 animal of this species will infallibly unite these qualities ; for its race 

 could not exist without them. But under these general conditions 

 there are particular ones, relative to the size, species, and haunts of 

 the prey, for which each animal is inclined ; and each of these 

 particular conditions result from modifications of the detail in the 

 formations which they derive from the general conditions ; thus, 

 not only the class, but the order, the genus, and even the species, are 

 detected in the formation ©f each part. 



For, that the jaw may be enabled to seize, it must have a certain 

 shaped prominence for the articulation, a certain relation between the 

 position of the resisting power and that of the strength employed with 

 the fulcrum : a certain volume in the temporal muscle, requiring an 

 equivalent extent in the hollow which receives it, and a certain con- 

 vexity of the zygomatic arch under which it passes : this zygomatic 

 arch must also possess a certain strength, to give strength to the mas- 

 seter muscle. 



That an animal may carry off his prey, a certain strength is requi- 

 site in the muscles which raise the head ; whence results a determinate 

 formation in the vertebrae or the muscles attached, and in the occiput 

 where they are inserted. 



That the teeth may cut the flesh, they must be sharp ; and they 

 must be so more or less, according as they will have, more or less ex- 



