SELECTION BY MAN 45 



he does of the intermediate links in the long lines of descent, 

 yet admit that many of our domestic races are descended 

 from the same parents — may they not learn a lesson of cau- 

 tion, when they deride the idea of species in a state of nature 

 being lineal descendants of other species? 



PRINCIPLES OF SELECTION ANCIENTLY FOLLOWED, AND 



THEIR EFFECTS 



Let us now briefly consider the steps by which domestic races 

 have been produced, either from one or from several allied 

 species. Some effect may be attributed to the direct and defi- 

 nite action of the external conditions of life, and some to 

 habit; but he would be a bold man who would account by 

 such agencies for the differences between a dray- and race- 

 horse, a greyhound and bloodhound, a carrier and tumbler 

 pigeon. One of the most remarkable features in our domes- 

 ticated races is that we see in them adaptation, not indeed to 

 the animal's or plant's own good, but to man's use or fancy. 

 Some variations useful to him have probably arisen sud- 

 denly, or by one step ; many botanists, for instance, believe 

 that the fuller's teasel, with its hooks, which cannot be 

 rivalled by any mechanical contrivance, is only a variety of 

 the wild Dipsacus; and this amount of change may have sud- 

 denly arisen in a seedling. So it has probably been with the 

 turnspit dog; and this is known to have been the case with 

 the ancon sheep. But when we compare the dray-horse and 

 race-horse, the dromedary and camel, the various breeds 

 of sheep fitted either for cultivated land or mountain pasture, 

 with the wool of one breed good for one purpose, and that 

 of another breed for another purpose ; when we compare the 

 many breeds of dogs, each good for man in different ways ; 

 when we compare the game-cock, so pertinacious in battle, 

 with other breeds so little quarrelsome, with "everlasting 

 layers" which never desire to sit, and with the bantam so 

 small and elegant; when we compare the host of agricultural, 

 culinary, orchard, and flower-garden races of plants, most 

 useful to man at different seasons and for different purposes, 

 or so beautiful in his eyes, we must, I think, look further 

 than to mere variability. We cannot suppose that all the 



