446 THE EVOLUTION OF LIFE. 



win lias been the first to perceive. To him we owe the dis- 

 covery that natural selection is capable of producing fitness 

 between organisms and their circumstances ; and he, too, has 

 the merit of appreciating the immensely-important conse- 

 quences that follow from this. He has worked up an enormous 

 mass of evidence into an elaborate demonstration, that this 

 " preservation of favoured races in the struggle for life," is 

 an ever-acting cause of divergence among organic forms. 

 He has traced out the involved results of the process with 

 marvellous subtlety. He has shown how hosts of otherwise 

 inexplicable facts, are fully accounted for by it. In brief, he 

 has proved that the cause he alleges is a true cause ; that it 

 is a cause which we see habitually in action ; and that the 

 results to be inferred from it, are in harmony with the phe- 

 nomena which the Organic Creation presents, both as a whole 

 and in its details. Let us glance at a few of the more im- 

 portant interpretations which the hypothesis furnishes. 



A soil possessing some ingredient in unusual quantity, 

 may supply to a plant an excess of the matter required for a 

 certain class of its tissues ; and may cause all the parts formed 

 of such tissues to be abnormally developed. Suppose that 

 among these are the hairs clothing its surfaces, including 

 those which grow on its seeds. Thus furnished with some- 

 what longer fibres, its seeds, when shed, are carried a little 

 further by the wind before they fall to the ground. The 

 young plants growing up from them, being rather more 

 widely dispersed than those produced by other individuals of 

 the same species, will be less liable to smother one another ; 

 and a greater number may therefore reach maturity and 

 fructify. Supposing the next generation subject to the same- 

 peculiarity of nutrition, some of the seeds borne by its mem- 

 bers will not simply inherit this increased development of 

 hairs, but will carry it further ; and these, still more advan- 

 taged in the same way as before, will, on the average, have 

 still more numerous chances of continuing the race. Thus, 

 by the survival, generation after generation, of those possess- 



