64 DARWINISM AND HUMAN LIFE 



mammals like the quagga should have been exter- 

 minated, but it is practically much more deplorable 

 that we have lost so many hawks and weasels 

 and other members of that pertinacious army 

 whose guerilla warfare keeps hundreds of more 

 humdrum creatures up to the scratch, and keeps 

 " vermin " from becoming a plague. Moreover, 

 it is extremely diflicult to tell what may be the 

 consequences of exterminating any creature — 

 remote as it may seem from the beaten track of 

 human affairs. One of the obvious lessons of 

 Darwinism is that we should be slow to call any 

 change unimportant. Everything counts, or may 

 count. A so-called unimportant animal is destroyed 

 and no immediate ill effects are seen. But who 

 can tell ? 



Very pertinent, for instance, is the question : 

 What about the parasites that used to complete 

 their life-history in romantic routine in this ex- 

 tinguished animal ? Have we extinguished the 

 parasite also ? Or is it waiting, with a whip of 

 scorpions, to chastise mankind for their ignorance 

 of Darwinism ? 



The practical importance of recognising the 

 web of life has been proved by the heavy penalties 

 which man has often had to pay for disturbing 

 the balance of nature, careless of results and 

 ruthless of beauty, for not admitting that if we 

 would master Nature we must first understand 

 her. How much has Australia had to pay for 

 the introduction of rabbits in 1860, or America 

 for sparrows ? Sometimes the introduction has 

 been unconscious, and man has only to blame 

 himself for letting the intruder take hold, aa in 

 the case of the Phylloxera in France, or of the 



