Through this line of influence, and this only, can there exist any probability of diminishing the increase of inherited insanity. Governments and society encourage, and rightly so, the institution of the marriage relation; the family is the corner-stone of society, and on it are reared the fabrics of civilization and civil institutions. Probably from no other practice or custom does there ensue so large effects in the way of happiness, prosperity, morality, and well-being to the human race, as from that of marriage; but the conditions of a large part of the beneficent results of this institution, depend upon freedom from certain tendencies to disease. Communities and states are composed of units, and their strength and stability must depend upon that of the individuals composing them. Quite in the degree that disease or degenerations, physical or mental, exist in any community, in that measure prosperity and happiness are diminished; so that from the stand-point of political economy, even, it becomes of vast importance that the laws of hereditary influence should be more fully understood. The instinct of love, however, is so powerful in the vast majority of the human race, that it overrides almost all other considerations. Persons do not stop to consider consequences to themselves, or to those who are to come after; they are borne on by the considerations of a present fancy or sentiment, and there is reason to fear that any legal enactments, or regulations, even, in the present state of knowledge on this subject, would not be worth the paper on which they might be inscribed.