Page:The Hog.djvu/21

19 "It is possible that some of the caudal vertebræ may be missing.

"The Chinese was imported into this country for the purpose of improving our native sorts, with which it breeds freely, and the offspring are again fruitful. I, this winter, saw a fine litter of pigs by Sir Rowland Hill's African boar, imported with the female I described, the mother of which was a common pig; time will show whether they will be again fruitful.

"From what has been stated, the result appears to me to be, that either of the above three pigs must be considered as distinct species, (and which, should the offspring of the two latter again produce young, would do away with the theory of Hunter, that the young of two distinct species are not fruitful,) or we cannot consider osteological character a criterion of species.

"I have been induced to offer the above, not with any desire of species-making, but of adding something towards the number of recorded facts, by which the question what is a species, must be answered."

Closely-allied species may produce offspring fertile inter se, although we have no proof positive of the fact in the case in question; for when domestication produces decided differences of external form, why should it be difficult to admit of the extension of the differences to internal parts also, and especially to the osseous framework, on which the form and symmetry of the body so greatly depend, or why the law of variation should be confined in its influence to one part, and restricted from another. If it be admitted that the bones may be somewhat modified in length or stoutness, we see not why it is that a numerical variation in the bones of the vertebral column should be so great a stumbling-block, especially seeing that accidental (and perhaps hereditary) variations are far from being uncommon, both in men and others of the mammalia. We can easily conceive that a portion of the osseous system, offering in almost every species of quadruped some variation in the number of its constituent parts, should be also the most likely to exhibit such variation, where a species long subjected to the modifying influence of human control, has branched out into various breeds or races,