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Show 121 GOOD FROM CROS~ING. CHAP. XVII. thus unconsciously have acquired their dislike and even abhorrence of incestuous marriages, rather than that they should have diRcovered by reasoning and observation the evil results. The abhorrence occasionally failing is no valid argument against the feeling being instinctive, for any instinct may occasionally fail or become vitiated, as sometimes occurs with parental love and the social sympathies. In the case of man, the question \rhether evil follows from close interbreeding will probably never be answered by direct evidence, as he propagates his kind so slowly and cannot be subjected to experiment ; but the almost universal practice of all races at all times of avoiding closelyrelated marriages is an argument of considerable weight; and whatever conclusion we arrive at in regard to the higher animals may be safely extended to man. Turning now to Birds: in the case of the Fowl a whole array of author~ tics could be given against too close interbreeding. Sir J. Sebright l)OSitiVely asserts th~J,t he made many trials, and that his fowls, when thus treated, became long in the legs, small in tho body, and bad breeders.:?.> He pr.odu~ed the. famous S~bright Bantams by complicated crosses, and by breedmg m7and-m; and smce his time there has been much close interbreeding with these Bantams; and they are now notoriously bad breeders. I have seen Silver Bantams, directly descended from his stock, which had become almost as barron as hybrids; for not a single chicken had been that year hatched n:om two full nests of eggs. 1\Ir. Hewitt says that with those Banta~s the. storili~y of the male stands, with rare exceptions, in tho closest relatwn with thmr loss of certain secondary male characters : he adds," I have noticed, as a general rule, that even the slightest deviation :: from. f~minine character in .the tail of tho male Sebright- say the " el~ngatw?- ~y. only half an mch of the two principal tail-feathers-brmgs w:th It rmproved probability of increased fertility." 26 " Mr. :'Ynght s~ates 27 that 1\fr. Clark, "whose fighting-cocks were so " not?~Ious, contmued to breed from his own kind till they lost their dis" pos1t10n to fight, but st.ood. to be cut up without making any resistance, " and were s~ reduced m Size as to be under those weights required for " tho. best pnzes; b~1t on obtaining a cross from Mr. Leighton, they . ag~m resumed thmr former courage and weight." It should be borne m ~nd that game-cocks before they fought were always weighed so that nothing was left to tho imagination about any reduction or in~rease of 25 ' The Art of Improving the Breed,' p. 13. 26 ' The Poultry Book,' by w. B. Tegetmeier, 18G6, p. U5. 27 'Journal Royal Agricult. Soc.' 18±6, vol. vii. p. 205; see also Ferguson on the Fowl, pp. 83,317; see also 'The Poultry Book,' by Tegetmeicr, 1866, p. 135, with respect to tbe extent to which cock-fighters found that they could venture to breed in-and-in, viz., occasionally a ben with her own son· "but ~hey wcro cautious not to rcp;at the m-and-in brecuing." CnAP. XVII. EVIL FROM INTERBREEDING. 125 weight. Mr. Clark docs not seem to have bred from brothers and sisters, which is the most injurious kind of union; and he found, after repeated trials, that there was a greater reduction in weight in the young from a father paired with his daughter, than from a mother with her son. I may add that l\1r. Eyton, of Eyton, the well-known ornithologist, who is a large brooder of Grey Dorkings, informs me that they certainly diminish in size, and become less prolific, unless a cross with another strain is occasionally obtained. So it is with Malays, according to Mr. Hewitt, as far as size is concernod.28 An experienced writer 29 remarks that the same amateur, as is well known, seldom long maintains the superiority of his birds ; and this, he adds, undoubtedly is clue to all his stock " being of the same blood ;" hence it is indispensable that he should occasionally procure a bird of another strain. But this· is not necessary with those who keep a stock of fowls at different stations. Thus, Mr. Ballance, who has bred Malays for thirty years, and has won more prizes with these birds than any other fancier in England, says that breeding in-and-in does not necessru·ily cause deterioration; "but all depends upon how this is managed." "My plan " has been to keep about five or six distinct runs, and to rear about " two hundred or three hundred chickens each year, and select the best "birds from each run for crossing. I thus secure sufficient crossing to " prevent deterioration." 30 We thus see that there is almost complete unanimity with poultry-breeders that, when fowls are kept at the same place, evil quickly follows from interbreeding carried on to an extent which would be disregarded in the case of most quadrupeds. On the other hand, it is a generally received opinion that cross-bred chickens are the hardiest and most easily roared.31 1\ir. Tegetmeier, who has carefully attended to poultry of all breeds, says 32 that Dorking hens, allowed to run with Houdan or Crevecamr cocks, "produce in the early spring chickens that for size, hardihood, "early maturity, and fitness for the market, surpass those of any pure " breed that we have ever raised." Mr. Hewitt gives it as a general rule with fowls, that crossing the breed increases their size. He makes this remark after stating that hybrids from the pheasant and fowl are considerably larger than either progenitor : so again, hybrids from the male golden pheasant and hen common pheasant "ru·e of far larger size than either parent-bird." 33 To this subject of the increased size of hybrids I shall presently return. With Pigeons, breeders are unanimous, as previously stated, that it is absolutely indispensable, notwithstanding the trouble and expense thus caused, occasionally to cross their much-prized birds with individuals of another strain, but belonging, of comse, to the same variety. It deserves 2s ' The Poultry Book,' by W. B. •regetmeicr, 1866, p. 79. 29 ' 'l'he Poultry Chronicle,' 1854, vol. i. p. 43. 3° 'The Poultry Book,' by W. B. Tegctmeicr, 1866, p. 79. 31 ' The Poultry Chronicle,' vol. i. p. 89. 32 'The Poultry Boo~,' 1866, p. 210. 33 Ibid, 1866, p. 167; and 'Poultry Chronicle,' vol. iii., 1855, p. 15. |