We may deduce, then, the following summary of General Rules.
First. There should be a mutual adaptation in form and size, and indeed, in all important characteristics between the sire and the dam.
Second. If the mare be defective in any particular, do not breed her to a stallion having a similar, or even an opposite fault; but rather choose one perfect in that point.
Third. Avoid breeding exceedingly small mares with enormously large horses: distortions will generally be the result. For a mare of 16 hands, select a horse of not less than 15 hands; if she be too low or small, the horse may be an inch or two higher, but not of the tall or leggy kind.
Fourth. It is frequently the case that without any known cause, the blood of a certain strain of horses will not cross well with that of another. Such instances, when ascertained should be avoided.
Fifth. If the mare is of a good strain of horses but one which has degenerated in size from "in-breeding," the only remedy is to breed to the purest stallion that can be found, but of a different strain from hers, unless some ten or more generations removed.
Sixth. After breeding for several generations from males and females of one strain, it will generally be found beneficial to change to another entirely different. Degeneracy in size will generally result from a neglect of this rule.
