S42 SCIENCE PROGRESS 



estimate of the scope and nature of man's interference by 

 domestication in the process of evolution is widely current 

 and finds a footing even among the most enlightened evolu- 

 tionists. Theoretically Darwinism has put man in his proper 

 place in the world and killed the anthropocentric theory but in 

 practice the anthropocentric habit of mind dies harder and its 

 vestiges remain in our brains in spite of ourselves and influence 

 thought unawares. It seems to be vaguely supposed or un- 

 consciously assumed that by domestication a species is removed 

 from the operation of natural law but properly regarded 

 domestication is nothing but a radical alteration of the en- 

 vironment, in which a new set of qualities, including some and 

 excluding others of the old set, constitute fitness and secure 

 survival. Beyond confinement and slaughter man does nothing 

 but select the variations which Nature, constant in nothing but 

 change, invariably presents. We may consider domestication 

 broadly as a kind of symbiosis, comparable with though widely 

 differing from other kinds occurring lower in the scale of life, in 

 which two species find it to their common advantage to live 

 in close companionship. If it be objected that, in this case, the 

 advantage is one-sided, the answer is that the domesticated 

 beast secures at least the main advantage of nutrition and 

 reproduction, whilst the cultivated plant may be said to secure 

 everything it would wish, if it could wish for anything. Like 

 enlightened merchants, they have found their own advantage in 

 supplying the needs of others ; or perhaps they are more like 

 the unenlightened, who do so unconsciously or even in spite of 

 themselves. And another answer is that there is no law of 

 nature that in symbiosis the advantages of the partnership must 

 be equal. Parasitism may be considered as a kind of symbiosis 

 in which they certainly are not so. 



But, it may be said, breeders have never formed two species 

 out of one but only varieties which are always capable of inter- 

 breeding. The objection would have more weight if any one 

 could tell us what a species is. It is not denied that the 

 differences between domestic varieties of dogs and pigeons are 

 far more than enough to have constituted them separate species 

 or as some say even genera, if they had been found in a state of 

 nature ; whilst as for sterility, there are plenty of hybrids to 

 prove that it is not an essential but only an accidental feature ol 

 natural species ; and on the other hand, Darwin gave evidence 





