It may, perhaps, excite surprise that in the preceding discussion of prostitution scarcely a word has been said of venereal diseases.  In the eyes of many people, the question of prostitution is simply the question of syphilis.  But from the psychological point of view with which we are directly concerned, as from the moral point of view with which we cannot fail to be indirectly concerned, the question of the diseases which may be, and so frequently are, associated with prostitution cannot be placed in the first line of significance.  The two questions, however intimately they may be mingled, are fundamentally distinct.  Not only would venereal diseases still persist even though prostitution had absolutely ceased, but, on the other hand, when we have brought syphilis under the same control as we have brought the somewhat analogous disease of leprosy, the problem of prostitution would still remain.

Yet, even from the standpoint which we here occupy, it is scarcely possible to ignore the question of venereal disease, for the psychological and moral aspects of prostitution, and even the whole question of the sexual relationships, are, to some extent, affected by the existence of the serious diseases which are specially liable to be propagated by sexual intercourse.

Fournier, one of the leading authorities on this subject, has well said that syphilis, alcoholism, and tuberculosis are the three modern plagues.  At a much earlier period (1851) Schopenhauer in Parerga und Paralipomena had expressed the opinion that the two things which mark modern social life, in distinction from that of antiquity, and to the advantage of the latter, are the knightly principle of honor and venereal disease; together, he added, they have poisoned life, and introduced a hostile and even diabolical element into the relations of the sexes, which has indirectly affected all other social relationships.[220] It is like a merchandise, says Havelburg, of syphilis, which civilization has everywhere carried, so that only a very few remote districts of the globe (as in Central Africa and Central Brazil) are to-day free from it.[221]

It is undoubtedly true that in the older civilized countries the manifestations of syphilis, though still severe and a cause of physical deterioration in the individual and the race, are less severe than they were even a generation ago.[222] This is partly the result of earlier and better treatment, partly, it is possible, the result also of the syphilization of the race, some degree of immunity having now become an inherited possession, although it must be remembered that an attack of syphilis does not necessarily confer immunity from the actual attack of the disease even in the same individual.  But it must be added that, even though it has become less severe, syphilis, in the opinion of many, is nevertheless still spreading, even in the chief centres of civilization; this has been noted alike in Paris and in London.[223]