448 THE EVOLUTION OP LIFE. 



counted for by any other hypothesis, while the h3^pothesis of 

 evolution gives us a clue to it; we must include it among 

 the supports of this hypothesis which the facts of classifica- 

 tion furnish. 



§ 127. What shall we say of these leading truths when 

 taken together? That naturalists have been gradually com- 

 pelled to arrange organisms in groups within groups, and that 

 this is the arrangement which we see arises by descent, alike 

 in individual families and among races of men, is a striking 

 circumstance. That while the smallest groups are the most 

 nearly related, there exist between the great sub-kingdoms, 

 structural contrasts of the profoundest kind, cannot but im- 

 press us as remarkable, when we see that where it is known to 

 take place evolution actually produces these feebly-distin- 

 guished small groups, and these strongly-distinguished great 

 groups. The impression made by these two parallelisms, which 

 add meaning to each other, is deepened by the third parallel- 

 ism, which enforces the meaning of both — the parallelism, 

 namely, that as, between the species, genera, orders, classes, 

 &c., which naturalists have formed, there are transitional 

 types ; so between the groups, sub-groups, and sub-sub-groups, 

 which we know to have been evolved, types of intermediate 

 values exist. And thesG three correspondences between the 

 known results of evolution and the results here ascribed to 

 evolution, have further weight given to them by the fact, that 

 the kinship of groups through their lowest members is just 

 the kinship which the hypothesis of evolution implies. 



Even in the absence of these specific agreements, the broad 

 fact of unity amid multiformity, which organisms so strik- 

 ingly display, is strongly suggestive of evolution. Freeing 

 ourselves from pre-conceptions, we shall see good reason to 

 think with Mr. Darwin, "that propinquity of descent — the 

 only known cause of the similarity of organic beings — is the 

 bond, hidden as it is by various degrees of modification, 

 which is partly revealed to us by our classifications.^' When 



