THEORY OP THE EARTH. 103 



commencing our investigation by a careful survey 

 of any one bone by itself, a person who is suffi- 

 ciently master of the laws of organic structure, 

 may, as it were, reconstruct the whole animal to 

 which that bone had belonged. 



This principle is sufficiently evident, in its gene- 

 ral acceptation, not to require any more minute 

 demonstration ; but when it comes to be applied 

 in practice, there is a great number of cases in 

 which our theoretical knowledge of these relations 

 of forms is not sufficient to guide us, unless assisted 

 by observation and experience. 



For example, we are well aware that all hoofed 

 animals must necessarily be herbivorous, because 

 they are possessed of no means of seizing upon 

 prey. It is also evident, having no other use for 

 their fore-legs than to support their bodies, that 

 they have no occasion for a shoulder so vigorously 

 organized as that of carnivorous animals ; owing 

 to which, they have no clavicles or accromion pro- 

 cesses, and their shoulder-blades are proportion- 

 ally narrow. Having also no occasion to turn their 

 fore-arms, their radius is joined by ossification to 

 the ulna, or is at least articulated by gynglymus 

 with the humerus. Their food, being entirely her- 

 baceous, requires teeth with flat surfaces, on pur- 

 pose to bruise the seeds and plants on which they 

 feed. For this purpose also, these surfaces require 

 to be unequal, and are consequently composed of 



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