Evidences of Theory of Natural Selection. 295 



have been perfected by such an indirect agency of 

 natural selection as is here suggested ^. 



The third general class of facts which tell so im- 

 mensely in favour of natural selection as an important 

 cause of organic evolution, are those of domestication. 

 The art of the horticulturist, the fancier, the cattle- 

 breeder, &c., consists in producing greater and greater 

 deviations from a given wild type of plant or animal, 

 in any particular direction that may be desired for 

 purposes either of use or of beauty. Cultivated 

 cereals, fruits, and flowers are known to have been 

 all derived from wild species ; and, of course, the same 

 applies to all our domesticated varieties of animals. 

 Yet if we compare a cabbage rose with a wild rose, a 

 golden pippin apple with a crab, a toy terrier with any 

 species of wild dog, not to mention any number of other 

 instances, there can be no question that, if such differ- 

 ences had appeared in nature, the organisms presenting 

 them would have been entitled to rank as distinct 

 species — or even, in many cases, as distinct genera. 

 Yet we know, as a matter of fact, that all these 

 differences have been produced by a process of arti- 

 ficial selection, or pairing, which has been continuously 

 practised by horticulturists and breeders through a 

 number of generations. It is the business of these men 

 to note the individual organisms which show most 

 variation in the directions required, and then to 

 propagate from these individuals, in order that the 

 progeny shall inherit the qualities desired. The 

 results thus become cumulative from generation to 

 generation, until we now have an astonishing mani- 



' Note B. 



