12 DARWINISM chap. 



carefully save the best seed to sow and the finest or brightest 

 coloured animals to breed from, we shall soon find that an 

 improvement will take place, and that the average quality of 

 our stock will be raised. This is the way in which all our 

 fine garden fruits and vegetables and flowers have been pro- 

 duced, as well as all our splendid breeds of domestic animals ; 

 and they have thus become in many cases so different from 

 the wild races from which they originally sprang as to be 

 hardly recognisable as the same. It is therefore proved that 

 if any particular kind of variation is preserved and bred from, 

 the variation itself goes on increasing in amount to an 

 enormous extent ; and the bearing of this on the question of 

 the origin of species is most important. For if in each 

 generation of a given animal or plant the fittest survive to 

 continue the breed, then whatever may be the special 

 peculiarity that causes " fitness " in the particular case, that 

 peculiarity will go on increasing and strengthening so long as 

 it is useful to the species. But the moment it has reached its 

 maximum of usefulness, and some other quality or modifica- 

 tion would help in the struggle, then the individuals which 

 vary in the new direction will survive; and thus a species may 

 be gradually modified, first in one direction, then in another, 

 till it differs from the original parent form as much as the 

 greyhound differs from any wild dog or the cauliflower from 

 any wild plant. But animals or plants which thus differ in 

 a state of nature are always classed as distinct species, and 

 thus we see how, by the continuous survival of the fittest 

 or the preservation of favoured races in the struggle for life, 

 new species may be originated. 



This self-acting process which, by means of a few easily 

 demonstrated groups of facts, brings about change in the 

 organic world, and keeps each species in harmony with the 

 conditions of its existence, will appear to some persons so 

 clear and simple as to need no further demonstration. But 

 to the great majority of naturalists and men of science endless 

 difficulties and objections arise, owing to the wonderful variety 

 of animal and vegetable forms, and the intricate relations of 

 the different species and groups of species with each other ; 

 and it was to answer as many of these objections as possible, 

 and to show that the more we know of nature the more we 



