140 THE DOCTRINE OF DESCENT. 



that doubtful species are not exceptional, as the old school 

 was wont to imagine, but that it is merely owing to an 

 inadequate knowledge of the material out of which species 

 are constructed, that all species are not looked upon as 

 doubtful and artificial. 



Let us here again call to mind that in many thousand 

 cases the most rigid systematizers are unable to state 

 where their species begin and end; of which Darwin, 

 as an instance, cites a communication by H. C. Watson, 

 that 182 British plants, usually regarded as varieties, have 

 each been claimed as independent species by individual 

 botanists.*^ Darwin's immortal service consists in hav- 

 ing shown what is the power which operates upon the 

 existing variable individuals and species, and what re- 

 sults this operation must produce. He found the key 

 in the word which has become a badge and common 

 property of our age, " the struggle for life," * and has 

 thus given the foundation and theory of a doctrine of 

 which the truth had long before been manifest to an in- 

 tellect such as that of Lamarck. He founded the doc- 

 trine of Descent on the theory of selection, when he 

 proved that in nature the struggle for existence occa- 

 sions a selection of the best and fittest, comparable 

 to artificial breeding, and giving rise to new races and 

 new species. 



The struggle for life, this bellnin omnium contra omnes, 

 is, moreover, an undisputed and undeniable fact, which 

 we here accept in its widest relations. Not only does 

 the beast of prey war against the graminivorous animals, 

 which again strive to keep their balance by superior mul- 

 tiplication, speed, and cunning; the gradual advance of 



* For Wallace's share in this honour, see the end of this chapter. 



