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methods of nature. Consider how, by carefullj' selecting 

 trifling modifications, and breeding from these modified 

 forms, man has been enabled to produce and preserve stocks 

 so different as the di-ay horse, the Shetland pony, the hack 

 and the race horse ; dogs so diverse as the otter hound and 

 the grey hound, the lordly mastiff and the {esthetic pug. 



To this process are due the varieties of cattle ; the in- 

 numerable kinds of roses, of pelargoniums, of fuchsias ; the 

 vastly differing qualities of apples and of waU-fruits. Men 

 themselves, even those of the same nation, are, by the more 

 or less artificial selection of our social organization, born 

 adapted to their future avocations — the idler with the 

 bearing of his class, and the son of toil with shoulders equal 

 to his burden. 



It is foimd that the more the varieties of a species are 

 differentiated from each other, the less prolific are they in 

 crossing. Could anj^thing be more suggestive of the truth 

 of our thesis ? 



Tlie Imperfection of Structures affords another argument on 

 which I will not dwell, further than to state that it is not 

 uncommon to find structures which fulfil their functions 

 usefully to their possessor it is true, but very imperfectly 

 from an ideal standpoint. ^Vhatever imperfection we 

 might find in actual structure, we should not, if species were 

 separately and specially created, expect to find a defect in 

 the plan of their organization. But every oculist regards 

 that marvellous mechanism, the human eye, as no ideally 

 perfect structure, incapable of improvement, but as decidedly 

 capable of an improved reconstruction on optical principles. 

 This and other similar facts become comprehensible by the 

 theory we are considering. 



Moreover, throughout nature there are few instances of 

 the adaptation of one species of animal or plant to the advan- 

 tage of another species of animal or plant. Of direct and 

 exclusive adaptation, there is absolutely no evidence what- 

 ever. That they afford food for one another would appear to 

 be a doubtful benefit to the organism that happens to be 

 eaten ; and often the higher Kfe affords an agreeable 

 dietary to the lower. The law of nature is 



" Tlie good old rule, the simple plan. 

 That thej' should take who have the power, 

 And they should keep who can." 



This fact, in perfect harmony with natural selection and 



