40 SELECTION BY MAN. Cn.sr. I. 



yet admit that many of our domestic races are descended from 

 the same parents — may they not learn a lesson of caution, 

 when tlicy deride the idea of species in a state of nature being 

 lineal descendants of other species ? 



Princi2>les of Selection anciently foUoiccd, and their Effects. 



r^et us now briefly consider the steps by which domestic 

 races have been produced, either from one or from several 

 allied species. Some elTect may be attributed to the direct 

 and definite action of the external conditions of life, and some 

 little to habit ; but he would be a bold man who would ac- 

 count by such agencies for the differences between a dray and 

 race horse, a greyhound and bloodhound, a carrier and tumbler 

 jiigeon. One of the most remarkable features in our domesti- 

 cated 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 suddenl}-, or by 

 one step ; many botanists, for instance, ])elieve that the fuller's 

 teasel, with its hooks, which cannot be rivalled by any mechan- 

 ical contrivance, is only a variety of the wild Dipsacus ; and 

 this amount of change may have suddenly arisen in a seedling. 

 So it has probably been with tlie turnspit-tlog ; and tliis 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 very 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 Avith 

 the bantam so small and elegant ; w^hen we compare the host 

 of agricultural, culinary, orchard, and flower-garden races of 

 plants, most useful to man at dillerent seasons and for differ- 

 ent purposes, or so beautiful in his eyes, we must, I think, 

 look fi'rther than to mere variability. "We cannot sup]")ose 

 that all the breeds were suddenly produced as perfect and as 

 useful as we now see them ; indeed, in many cases, we know 

 that this has not been their history. The key is man's ])ower 

 of accumulative selection: Nature gives successive variations; 

 man a<lds them up in certain directions useful to him. In tliig 

 sense he may be said to have made for himself useful breeds. 



