152 BISET OR WILD ROCK-PIGEON. 



nerated all the various races and peculiar varieties, 

 which, it is well known, when once produced, may 

 be perpetuated for an indefinite period, by being 

 kept separate from, and unmixed with, others ; or 

 what, by those interested in such pursuits, is usual- 

 ly termed " breeding in and in." Such also, we may 

 add, is the opinion of the most eminent naturalists, 

 as to their origin, and it is strongly insisted on by 

 M. Temminck in his valuable work, the Histoire 

 Generale Naturelle des Pigeons. Indeed, the fact, 

 that all the varieties, however much they may differ 

 in colour, size, or other particulars, if permitted, 

 breed freely and indiscriminately with each other, 

 and produce a progeny equally prolific, is another 

 and a convincing proof of their common and self- 

 same origin ; for it is one of those universal laws of 

 nature, extending even to plants, and one which, if 

 once set aside or not enforced, would plunge all ani- 

 mated matter into indescribable confusion, that the 

 offspring produced by the intercourse of different, 

 that is, distinct species, is incapable of further in- 

 crease. That such an intercourse may be effected, 

 is well known to all ; but it is generally under pe- 

 culiar or artificial circumstances, and rarely when the 

 animals, birds, or whatever they may be, are in their 

 natural state, and in a condition to make their own 

 election. It is seen in the crosses obtained, in a 

 state of confinement, between the canary and gold- 

 finch, linnet, &c. ; in the hybrids produced between 

 different species of the Anatidae when domesticated, 



