In the prostitute, sexual contacts are too promiscuous, and she is too unreliable, to afford any very trustworthy information, further than may be judged by the aspect of one who has followed the business for a decade. It is little to know that her life, as a rule, is short and her social redemption next to impossible, and her entailed ills irremediable. When the habit of self-pollution is once established by a girl, it is worse than in the male; as a female is not so likely to yield to any sort of a vice as a male, and she will carry it to a greater extreme. Modesty and fear of giving offence will always impede the advancement of knowledge in regard to the sexual functions in the so-called chaste and unmarried. The married female’s sexual life and acts are often brought to the knowledge of her physician. I have often been asked the question, why so many married women become invalids from uterine and ovarian diseases? Not referring to child-bearing, abortions, and many indirect causes of disease which are numerous, but not enough to furnish an etiology for the long category of nervous ailments with which the medical man has to contend, my answer is, sexual abuse; a misunderstanding of the sexual functions; a non-adaptation of two individuals joined in marriage. It is not so commonly excessive venery; or too often repeated coition; but unrequited passion. Man is too likely to forget his duty to his wife and look first to his own gratification. Any sexual embrace not attended with sexual orgasm, is very detrimental and causes disease. With the brutal man and phlegmatic woman this condition is quite likely to occur, and more especially if the man has been a masturbator. Where the latter condition has caused a partial impotency, the sexual orgasm very commonly occurs before or immediately after the intromission of the penis, in which condition beatitude is impossible, and the physician is most likely to be consulted by one of the parties. It will not improve our knowledge to be too modest on this question. As medical men we have the diseases of the sexual organs and their _sequelæ_ to treat, and we must discuss the causes. My suggestion, that a couple should be matched, sexually, seems not out of place; and if this condition is not present at first, it must be obtained by adaptation. My observation has been supplied with a number of instances of once faithful wives, who had forsaken their husbands for this seeming little discrepancy or neglect, and associated themselves happily with more adaptable mates. These singular facts confront us, and as teachers and scientific men we may, when consulted, if familiar with the causes, suggest remedies. I have many times corrected this discrepancy in domestic felicity by a little careful instruction, and thereby prevented the impending dissolution of the marriage relation. This might well be termed matrimonial hygiene.