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find also that generally the more perfect structure of the fore part of 

 the body prevails in carnivorous animals, but that in herbivorous ani- 

 mals the hind part is usually the larger. 



When in two groups of different tribes of animals there is a cor- 

 responding development of the body toward the positive pole, or to- 

 ward the negative pole, or of the same organs or members or functions 

 at either end, the conformation has been often expressed by the term 

 analogy. 



We next proceed to show how intimately allied to this law is the 

 study of the growth and metamorphose of the species, and that of 

 comparative anatomy, for when one pole — that is, the body adjoin- 

 ing to it — is much developed, the other end is small in proportion. 

 With this may be mentioned the law of the balance of organs, or 

 of the predominance of one organ at the expense of another, for 

 when the former is distinct or very large the latter fails or almost 

 ceases. The cause of this is the matter elaborated from food being 

 carried toward one pole in a greater degree than toward the other, 

 or to one organ rather than to another. It has been observed also 

 that each segment or member in the range of species has an origin, 

 dominion and cessation, both as to size and function, according 

 as the matter above mentioned reaches it in small or in large quan- 

 tities, or finally disappears from it ; and thus the infinite variety 

 of animal forms is effected. And the mode of development or meta- 

 morphose of animals is occasioned by the elaborated matter ceasing 

 from one part of Uie body, and being carried to another part which 

 before had scarcely received it, and by this process one part of 

 the body is diminished in size, and its appendages cease, while other 

 segments and their members are considerably increased, and acquire 

 new functions. Thus it has been observed that when a caterpillar is 

 changing into a butterfly, the matter accumulated from food and dis- 

 tributed along the body is carried toward the poles to develope the 

 organs which before were scarcely perceptible. 



The more an animal inclines toward the negative pole, the more 

 remarkable it is for reproduction, and for tenacity, and diffusion, and 

 inertness of life ; but the nearer a creature approaches to the positive 

 pole, the more it has individuality, and concentration, and perfection 

 of life, which however becomes more precarious and less reproductive, 

 and there life parts from matter, by which at the other end it is ab- 

 sorbed ; and thus these poles, like life and death, are the bounds and 

 limits of creation. 



In glancing over the animal kingdom, the following examples are a 



