While paying much attention to venereal diseases and their consequences, medicine has shown itself inconceivably blind in not comprehending the bearing of this elementary arithmetic. We must take into account the fact that the complete cure of syphilis is very difficult, if not impossible, to prove; that this disease is extremely infectious, at least during the first two years of its course; and that it extends to the blood and the whole organism, so that it may be communicated, not only by large visible sores, but by small excoriations hidden in the mucous membrane of the vagina or the mouth, etc. We must also remember that gonorrhea is less painful in woman than in man, and that, even in the latter, it ceases to be painful when it becomes chronic. We may add that the microbes (the gonococci) are very difficult to reach in all the recesses of the mucous membrane of the sexual organs in which they are hidden, and that in women they penetrate as far as the womb, when a cure becomes almost impossible. If we consider that the sexual organs of woman form deep and hidden cavities which it is very difficult to examine thoroughly, in spite of all the apparatus of modern surgery, and that the mouth in prostitutes is also frequently contaminated by unnatural manipulations; lastly, that no part of their body is absolutely indemnified, it is easy to understand the great danger of infection in public prostitution. Recognizing the danger of venereal disease, the regulation of prostitution was instituted by medical men with the good intention of eliminating or of diminishing its danger, since they regarded its suppression as impossible. This system consists in the official supervision and inscription of every woman who prostitutes herself. She is given an official form which obliges her to submit to medical examination once a week or once a fortnight, under the penalty of being arrested and punished. To facilitate medical control, regulation generally endeavors to lodge prostitutes in brothels or _lupanars_, under the direction of a proxenet. In theory, the brothel is not exactly considered as a State institution of public health; the word _toleration_ being used in this connection, signifying that it is regarded as a tolerated evil. Nevertheless, this distinction only rests on uncertain and subtle characters. To tolerate, to license, to organize, to recognize and favor, to protect and recommend are notions which merge into one another insensibly. As soon as the State tolerates prostitution and brothels, it is obliged to enter into official contracts with prostitutes and proxenetism; therefore, it recognizes them. Moreover, the services which it renders must be paid for. It is therefore necessary that prostitutes and proxenets should pay their tribute to the State and to the doctors: but "the one who pays commands."