The same gentleman also obtained a pair of wild geese from Canada in 1818, which with their progeny were bred from without change until destroyed by dogs with the above named in 1852. They continued perfect as at first.
Among gregarious ruminating animals in a state of nature, all who associate in a herd acknowledge a chieftain, or head, who maintains his position by virtue of physical health, strength and general superiority. He not only directs all their movements but is literally the father of the herd. When a stronger than he comes, the post of chieftain and sire is yielded, but in all probability his successor is one of his own sons, who in turn begets offspring by his sisters. The progeny inheriting full health, strength and development, the herd continues in full power and vigor,[23] and does not degenerate as often happens when man assumes to make the selections, and chooses according to fancy or convenience. The continuance of health, strength and perfect physical development is believed to depend on the wisdom of the selection, upon the presence of the desirable hereditary qualities, and the absence of injurious ones, and not upon relationship whether near or remote.
It has fallen within the observation of most persons that in the human race frequent intermarriages in the same family for successive generations often tend to degeneracy of both mind and body; size and vigor diminishing, and constitutional defects and diseases being perpetuated and aggravated; but neither in this case is the result believed to be a necessary and inevitable consequence. Else how could it be, that Infinite Wisdom, whose operations are ever in accordance with the laws of his own institution, in originating a "peculiar people," chosen to be the depositories of intellectual and physical power, wealth and influence, and who, in spite of oppression without parallel in the world's history, have ever maintained the possession of a goodly share of all these,—would have allowed their first progenitor, Abraham, to marry his near kinswoman Sarah, a half sister, niece or cousin, and Isaac their son to wed his first cousin Rebecca, and Jacob who sprang from that union, to marry first cousins, and their offspring for long generations to intermarry within their own people and tribes alone? At a later period, marriages within certain degrees of consanguinity were forbidden by Divine authority, but not until the peculiar race was fully established, and so far multiplied, as to allow departure from close breeding without change of characteristics, and not improbably the prohibition was even then based more upon moral reasons, or upon man's ignorance or recklessness regarding selection, than upon physical law.
Such laws exist among us at present, and it is well they do, inasmuch as for the reasons already given there is greater probability of degeneracy by means of such connections than among those not so related by blood. But they present an instance of the imperfection of human laws, it being impossible for any legal enactments to prevent wholly the evil thus sought to be avoided. It would be better far, if such a degree of physiological knowledge existed and such caution was exercised among the community generally, as would prevent the contraction of any marriages, where, from the structure and endowments of the parties, debility, deformity, insanity or idiocy must inevitably be the portion of their offspring whether they are more nearly related than through their common ancestor, Noah, or not.
If we adopt Mr. Walker's views, it is easy to see how parents of near affinities may produce offspring perfect and healthy, or the reverse. He holds, that to secure satisfactory results from any union, there should be some inherent, constitutional, or fundamental difference; some such difference as we often see in the human family to be the ground of preference and attachment; as men generally prefer women of a feminine rather than a masculine type. All desire, in a mate, properties and qualities not possessed by themselves. Now assuming as Mr. Walker holds, that organization is transmitted by halves, and that, in animals of the same variety, either parent may give either series of organs, we can see in the case of brother and sister that if one receives the locomotive system of the father and the nutritive system of the mother, and the other the locomotive system of the mother and the nutritive system of the father, they are essentially unlike, there is scarcely any similarity between them, although, as we say, of precisely the same blood; and their progeny if coupled might show no deterioration; whereas, if both have the same series of organs from the same parents, they would be essentially the same, a sort of quasi identity would exist between them, and they are utterly unfit to be mated. There might be impotency, or barrenness, or the progeny, if any, would be decidedly inferior to the parents; and the same applies, more or less, to other relatives descended from a common ancestry, but more distant than brother and sister. Mr. Walker also holds that where the parents are not only of the same variety but of the same family in the narrowest sense, the female always gives the locomotive system and the father the nutritive; in which case the progeny is necessarily inferior to the parents.
A careful consideration of the subject brings us to the following conclusions, viz:
That in general practice, with the grades and mixed animals common in the country, close breeding should be scrupulously avoided as highly detrimental. It is better always to avoid breeding from near affinities whenever stock-getters of the same breed and of equal merit can be obtained which are not related. Yet, where this is not possible, or where there is some desirable and clearly defined purpose in view, as the fixing and perpetuating of some valuable quality in a particular animal not common to the breed, and the breeder possesses the knowledge and skill needful to accomplish his purpose, and the animals are perfect in health and development, close breeding may be practiced with advantage.
FOOTNOTES:
[20] Mr. Bates, although eminent as a breeder, was not infallible in making his selections, and after long continued close breeding, he was compelled to go out of his own herd to procure breeding animals.