Chap. I.] SELECTION BY MAN". 35 



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 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 power of accumulative selection : nature gives 

 successive variations ; man adds them up in certain 

 directions useful to him. In this sense he may be said 

 to have made for himself useful breeds. 



The great power of this principle of selection is not 

 hypothetical. It is certain that several of our eminent 

 breeders have, even within a single lifetime, modified to 

 a large extent their breeds of cattle and sheep. In 

 order fully to realise what they have done, it is almost 

 necessary to read several of the many treatises devoted 

 to this subject, and to inspect the animals. Breeders 

 habitually speak of an animal's organisation as some- 

 thing plastic, which they can model almost as they 

 please. If I had space L could quote numerous pas- 

 sages to this effect from highly competent authorities. 

 Youatt, who was probably better acquainted with the 

 works of agriculturists than almost any other indi- 

 vidual, and who was himself a very good judge of 

 animals, speaks of the principle of selection as "that 

 which enables the agriculturist, not only to modify the 

 character of his flock, but to change it altogether. It 

 is the magician's wand, by means of which he may 

 summon into life whatever form and mould he 

 pleases." Lord Scmerville, speaking of what breeders 

 have done for sheep, says : — " It would seem as if they 



