364 THE EVOLUTION OF LIFE. 



parallelisms, which, add meaning to each other, is deepened 

 by the third parallelism, 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 gradations ; so between the groups, 

 sub-groups, and sub-sub-groups, which we know to have 

 been evolved, groups of intermediate values exist. And 

 these three correspondences between the known results of 

 evolution, and the results here ascribed to evolution, have 

 further weight given to them by the circumstance, 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 we 

 consider that this only known cause of similarity, joined with 

 the only known cause of divergence, which we have in the 

 influence of conditions, gives us a key to these likenesses 

 obscured by unlikenesses, to which no consistent interpreta- 

 tion can otherwise be given, even if purely hypothetical 

 causes be admitted; we shall see that were there none of 

 those very remarkable harmonies above pointed out, the 

 truths of classification would still yield strong support to our 

 conclusion. 



