If further proof of the possibility of the long-continued interbreeding of cattle is needed, it may be found on page 44 of The Westminster Review for July, 1863. This review is the stronghold of Darwinism. The writer of the article to which we refer says, that "Dr. Child gives the pedigree of the celebrated bull Comet and of some other animals, bred with a degree of closeness such as no one who has not studied the subject would believe possible. In one of these cases, the same animal appears as the sire in four successive generations." So striking is the pedigree of Comet, that the writer cannot refrain from inserting it.
The sheep is another animal in which there is an approximation to proportionate development. Let us see, then, if our doctrine equally obtains in this case. Before going further, we may request the reader to call to mind Darwin's assurance that his remark, "that extremely close interbreeding may be long carried on with cattle," is equally applicable to sheep.
On page 119, vol. ii., he remarks that,
"With sheep there has often been long-continued close interbreeding within the limits of the same flock; but whether the nearest relations have been matched so frequently as in the case of shorthorn cattle, I do not know. The Messrs. Brown, during fifty years, have never infused fresh blood into their excellent flock of Leicesters. Since 1810, Mr. Barford has acted on the same principle with the Foscote flock. He asserts that half a century of experience has convinced him that when two nearly-related individuals are quite sound in constitution, in-and-in breeding does not induce degeneracy; but he adds that he 'does not pride himself on breeding from the nearest affinities.' In France, the Naz flock has been bred for sixty years without the introduction of a single strange ram."
In connection with this subject The Westminster Review says that,
"M. Beaudouin, in a memoir to be found in the Comptes Rendus of August 5th, 1862, gives some very interesting particulars of a flock of merino sheep bred in-and-in, for a period of two and twenty years, without a single cross, and with perfectly successful results, there being no sign of decreased fertility, and the breed having in other respects improved."
Of all animals, the horse is manifestly the most proportionately developed. In him all the parts maintain, to a great extent, the due proportions. Our doctrine, then, leads us to expect that, in this case, little evil results from close interbreeding. We would be greatly surprised that the horse was not the most striking instance of the possibility of long-continued in-and-in breeding, were we not conscious of the fact that a great portion of the evil eventually resulting from close interbreeding is attributable to augmentation of the diseases to which the horse is singularly susceptible. The following is the only evidence we shall adduce in the case of the horse; but it "is clear and decisive":
"Mr. J. H. Walsh, well known, under the nom de plume of Stonehenge, as an authority upon sporting matters, says distinctly, in his recent work, that nearly all our thorough-bred horses are bred in-and-in." (Vide West. Rev. for July, 1863, p. 44.)
"Writers upon sporting matters are pretty generally agreed that no horse either bears fatigue so well or recovers from its effects so soon as the thorough-bred, and it is a subject upon which such writers are the best of all authorities. Thus, 'Nimrod' concludes a comparison between the thorough-bred and the half-bred hunter in the following words: 'As for his powers of endurance under equal sufferings, they doubtless would exceed those of the 'cock-tail,' and being by his nature what is termed a better doer in the stable, he is sooner at his work again than the others. Indeed, there is scarcely a limit to the work of full-bred hunters of good form and constitution and temper; and yet these, as we have seen, are almost all close bred." (Ibid. p. 45.)
The mention of "good form" is a fact of significance; for the current conception of symmetry is, in the case of the horse, a safer criterion of proportionate development than in the case of any other animal.