=Two Individuals of Tubercular Stocks Should Not Marry.--=However, sufficient is now known of the inheritance of susceptibility to the disease that we can have little conscience toward the welfare of the race if we in any way countenance the marriage of two individuals who come each of tubercular strains, and marriage of even a normal person into a badly tainted strain, where the one married is tubercular, is extremely hazardous looked at from the standpoint of the children likely to be born of such a union. The Supreme Court of New York recently held that the fraudulent concealment of tuberculosis by a person entering into a marriage relation is ground for the annulment of the marriage. =Special Susceptibility Less of a Factor in Many Diseases.--=With some diseases such as leprosy, typhoid fever, smallpox and cholera there seems to be less a question of special susceptibility since nearly all persons are vulnerable. Yet in cases of typhoid, at least, there are some indications that certain families are more likely to take the disease than others under similar exposure. We know of no inherited effects of such diseases, however. For instance, children of lepers do not inherit leprosy and if kept out of leper districts remain normal. =Deaf-Mutism.--=In certain abnormal states there is danger of confusing similar conditions which may have two entirely different sources of origin. Deafness, for example, may be strictly inborn as the outcome of a germinal variation or it may result from extraneous influences such as accidents, infective diseases, neglected tonsils and the like. The former is inheritable, the latter not. Bell in 1906 in a special census report to the United States government showed that deaf-mutism is markedly hereditary, particularly where deaf-mutes intermarry as they are prone to do. Fay's extensive studies on _Marriage of the Deaf in America_ also demonstrate the hereditary nature of the congenital forms of deafness. Cut off as such individuals are from communication with normal people, the association of the two sexes in special schools and institutions is of course highly conducive to such marriages. The defect seems to behave in the manner of a Mendelian recessive. Two deaf-mutes should not have children and yet such marriages are occurring every day. Even if two persons marry from families which tend to become hard of hearing the evidence indicates that their children are likely also to develop this partial deafness as they grow older, although it seems safe for a person of such tendency to marry into a family without it.