This must not always be! It is neither wise nor right that the essential matters of human life should always remain a stumbling block and a rock of offense for the children of men. We are coming to see that sex is no more unclean and to be denied a scientific knowledge of, than any other part of the human body--the eye, the ear or whatsoever. Furthermore, the rank and file are beginning to clamor for a knowledge of these matters for themselves. This is shown by the frequency of articles that deal with sex in many of the best newspapers and magazines in the civilized world, and by similar discussions in the literature, the works and scientific books that now go into the hands of the common people. It also shows in the attempts that are occasionally being made to introduce the subject of sexual hygiene into our public schools and other educational institutions. "The world do move!" It is for these reasons--because it is right to transfer to you and to those who come after, the sex knowledge that has been acquired by the author, by reading scientific and professional literature upon the subject, by conference with men and women who know, and by personal and professional experience, that what follows is written. III THE CORRECT MENTAL ATTITUDE So much by way of general remarks regarding the subject in hand. It is more the especial purpose of what follows, however, to treat of the matter of marriage in particular, _to say something definite to young husbands and wives that shall be of real benefit to them_, not only by way of starting them out right in the new and untried way upon which they have entered, but to help them to make that way a realm of perpetual and ever increasing joy to both parties concerned, throughout its entire course, their whole lives long. Be it said, then, first, that it is the duty of every bride and groom, before they engage in sexual commerce with each other, to acquaint themselves thoroughly with the anatomy and physiology of the sex organs of human beings, both male and female, and to make the acquirement of such knowledge as dispassionate and matter-of-fact an affair as though they were studying the nature, construction and functions of the stomach, or the digestive processes entire, or the nature and use of any of the other bodily organs. "Clear and clean am I within and without; clear and clean is every scrap and part of me, and no part shall be held more sacred or preferred above another. For divine am I, and all I am, or contain."