THE CROSSING, AC, OF PIGEONS AND FOWLS. 249 



Plants, &C.), " CAN MOST READILY BE ACQUIRED IN THE 

 CASE OF ANIMALS SUCH AS FpWLS, PlGEONS, &C. * * 



Now, I have inquired of very many breeders of these 

 birds, and / have hitherto not met with a single man 

 who was not thoroughly convinced, that an occasional 

 cross with another strain of the same sub-variety, was 

 not absolutely necessary. Most breeders of highly im- 

 proved, or fancy birds, value their own strain, and are 

 most unwilling, at the risk, in their Opinion, of deterio- 

 ration, to make a cross. The purchase of a first-rate 

 bird, of another strain, is expensive, and exchanges 

 are troublesome ; yet all breeders, as far as I can hear, 

 excepting those who keep large stocks, at different 

 places, for the sake of crossing, are driven, after a 

 time, to take this step!' 



The reason, why " evidence of the evil effects of 

 close -interbreeding, can most readily be acquired, in 

 the case of animals, such as Pigeons, Fowls, &c," is in- 

 soluble by Darwin. He simply records the fact, with- 

 out attempting to explain it. The real reason, is, be- 

 cause the varieties of these species are divergent in char- 

 acter; and divergence necessarily implies dispropor- 

 tionate development. For, it takes many positive char- 

 acters to make many divergent varieties, and such char- 

 acters, instead of forming peculiarities of several classes 

 within the same species, are all, according to the theory 

 of reversion, needed in each individual of the species. 

 Consequently, it is to be expected, that, when these 

 characters, instead of being concurrently developed, in 

 each individual, are apportioned among different varie- 

 ties, and when the true integrity of the species, is thus 

 impaired, some evil or injury must follow ; and, as 



Pigeons and Fowls are the species, wherein the true 

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