60 MESSBS. C. DAEWIN AND A. WALLACE ON THE 



its body that is not called into daily and hourly activity ; there is 

 no sense or faculty that is not strengthened by continual exercise. 

 The domestic animal, on the other hand, has food provided for it, 

 is sheltered, and often confined, to guard it against the vicissitudes 

 of the seasons, is carefully secured from the attacks of its natural 

 enemies, and seldom even rears its young without human assistance. 

 Half of its senses and faculties are quite useless ; and the other 

 half are but occasionally called into feeble exercise, while even its 

 muscular system is only irregularly called into action. 



Now when a variety of such an animal occurs, having increased 

 power or capacity in any organ or sense, such increase is to- 

 tally useless, is never called into action, and may even exist without 

 the animal ever becoming aware of it. In the wild animal, on the 

 contrary, all its faculties and powers being brought into full action 

 for the necessities of existence, any increase becomes inunediately 

 available, is strengthened by exercise, and must even slightly mo- 

 dify the food, the habits, and the whole economy of the race. It 

 creates as it were a new animal, one of superior powers, and which 

 will necessarily increase in numbers and outlive those inferior 

 to it. 



Again, in the domesticated animal all variations have an equal 

 chance of continuance ; and those which would decidedly render a 

 wild animal unable to compete with its fellows and continue its 

 existence are no disadvantage whatever in a state of domesticity. 

 Our quickly fattening pigs, short-legged sheep, pouter pigeons, 

 and poodle dogs could never have come into existence in a state 

 of nature, because the very first step towards such inferior forms 

 would have led to the rapid extinction of the race ; still less 

 could they now exist in competition with their wUd allies. The 

 great speed but slight endurance of the race horse, the unwieldy 

 strength of the ploughman's team, would both be useless in a 

 state of nature. If turned wild on the pampas, such animals would 

 probably soon become extinct, or under favourable circumstances 

 might each lose those extreme qualities which would never be called 

 into action, and in a few generations would revert to a common 

 type,'which must be that in which the various powers and faculties 

 are so proportioned to each other as to be best adapted to procure 

 food and secure safety, — that in which by the full exercise of every 

 part of his organization the animal can alone continue to live. 

 Domestic varieties, when turned wild, must return to something 

 near the type of the original wild stock, or hecome altogether 

 extinct. 



