Hardly any point has been more warmly debated by medical men. It has been said that in such marriages the woman is more apt to be sterile; that if she have children, they are peculiarly liable to be born with some defect of body or mind,--deafness, blindness, idiocy, or lameness; that they die early; and that they are subject, beyond others, to fatal hereditary diseases, as cancer, consumption, scrofula, etc. An ardent physician persuaded himself so thoroughly of these evils resulting from marriage of relatives, that he induced the Legislature of Kentucky to pass a law prohibiting it within certain degrees of consanguinity. Many a married couple have been rendered miserable by the information that they had unwittingly violated one of nature's most positive laws. Though their children may be numerous and blooming, they live in constant dread of some terrible outbreak of disease. Many a young and loving couple have sadly severed an engagement, which would have been a prelude to a happy marriage, when they were informed of these disastrous results. For all such we have a word of consolation. We speak it authoritatively, and not without a full knowledge of the responsibility we assume. The risk of marrying a cousin, even a first cousin, is greatly diminished, provided there is no decided hereditary taint in the family. And when such hereditary taint does exist, the danger is little more than in marrying into any other family where it is also found. Indeed, a certain German author has urged the propriety of such unions, where the family has traits of mental or physical excellence, as a means of preserving and developing them! So far as sterility is concerned, an examination of records shows, that whereas in the average of unions one women in _eight_ is barren, in those between relatives but one in _ten_ is so. And as for the early deaths of children, while, on an average, fifteen children in a hundred die under seven years, in the families of nearly-related parents but twelve in a hundred is the mortality as shown by French statistics. The investigations about idiotic and defective children are by no means satisfactory, and are considered by some of the most careful writers as not at all proving a greater tendency to such misfortunes in the offspring of cousins. Among a thousand idiotic children recently examined in Paris, not one was descended from a healthy consanguinity. But as few families are wholly without some lurking predisposition to disease, it is not well, as a rule, to run the risk of developing this by too repeated unions. Stock-breeders find that the best specimens of the lower animals are produced by crossing nearly-related individuals a certain number of times; but that, carried beyond this, such unions lead to degeneracy and sterility. Such, also, has been the experience of many human families.