INTRODUCTION. 19 



not have been, from the beginning, several varieties of the 

 same species, endowed with different qualities, and instincts, 

 and propensities, adapting them to the situation in which 

 they are found, is one of considerable interest to the zoolo- 

 gist, but with which the breeder of any species of animal 

 has little to do. It is also a question difficult to solve — 

 it is one that does not admit of demonstrative proof either 

 the one way or the other, and on which it does not become 

 the candid inquirer to speak positively and with arrogance. 



These observations are induced by the careless and pre- 

 sumptuous way in which almost every natural historian at 

 once settles the matter. He does not seem to admit of any 

 doubt respecting the affair, but at once assumes it as a cer- 

 tainty that every species of animal was derived from one 

 original parent, and sets himself to work to inquire which 

 was the parent breed, and, worse than all, derives many fan- 

 ciful, nay, even some practical conclusions from that which 

 rests at best only on probability. Thus there is scarcely a 

 writer on sheep who does not take the question at once for 

 granted, and describe the Argali, or the Musmon, or some 

 creature of his own imagination, as the common origin of all. 



There is no doubt that one variety of domesticated ani- 

 mals, if prevented from mixing with any other, will in gene- 

 ral propagate the same kind without any material change. 

 It is also acknowledged that if, from some unknown or ac- 

 cidental cause, an individual is produced, possessing some un- 

 usual peculiarities, his progeny, to a certain degree, will 

 probably possess the same peculiarities ; and if a male and 

 a female are selected with these peculiarities, and care is af- 

 terwards taken to exclude all who have them not, a new and 

 permanent breed may be established. It is likewise suffi- 

 ciently clear, that climate, soil, and pasture will gradually 

 effect a considerable change in the form and the quality both 

 of the wool and the flesh of every breed. These changes, 

 however, have their limits ; they go no farther than producing 

 modifications of the former breed : the essential and distin- 

 guishing character may yet be recognised, or, if it should 

 be rendered somewhat obscure, it will burst forth again 

 when the animal regains his native soil and climate. 



The question is, when there are varieties of a species es- 

 sentially and altogether different from each other ; when the 

 act of man has and could have little to do in effecting such a 

 difference ; when there was nothing to prevent that inter- 



