THE 



VARIATION OF ANIMALS AND PLANTS 



UNDEK DOMESTICATION". 



INTRODUCTION. 



The object of this work is not to describe all the many races 

 of animals which have been domesticated by man, and of 

 the plants which have been cultivated by him; even if I 

 possessed the requisite knowledge, so gigantic an undertaking 

 would be here superfluous. It is my intention to give under the 

 head of each species only such facts as I have been able to col- 

 lect or observe, showing the amount and nature of the changes 

 which animals and plants have undergone whilst under man's 

 dominion, or which bear on the general principles of varia- 

 tion. In one case alone, namely in that of the domestic 

 pigeon, I will describe fully all the chief races, their history, 

 the amount and nature of their differences, and the probable 

 steps by which they have been formed. I have selected this 

 case, because, as we shall hereafter see, the materials are better 

 than in any other ; and one case fully described will in fact 

 illustrate all others. But I shall also describe domesticated 

 rabbits, fowls, and ducks, with considerable fulness. 



The subjects discussed in this volume are so connected that 

 it is not a little difficult to decide how they can be best arranged. 

 I have determined in the first part to give, under the heads of 

 the various animals and plants, a large body of facts, some 

 of which may at first appear but little related to our subject, 

 and to devote the latter part to general discussions. When- 

 ever I have found it necessary to give numerous details, in 

 support of any proposition or conclusion, small type has been 



