=Education on These Subjects Necessary.=--It is not the purpose of this book to moralize upon these themes, or to say what should and should not be done; but knowing something of the wretchedness of womankind, and the fearful slavery she often has to endure, I can only hope, with all my heart, that the coming generation may be better educated on these most important topics. It is with a thought or two of this kind in mind that I append the following brief outline of this subject:-- =Two Sexes Necessary.=--In the higher animals two sexes are necessary for the reproduction of the race, the male and the female. Each contributes some particular element toward the beginning of a new life; this is known as the germ-cell. =The Germ-Cells.=--The germ-cells of the male are called spermatozoa, and those of the female, ova. The reproductive process is simply a fusion, or union of these male and female germ-cells. =The Male Elements.=--The spermatozoa are exceedingly delicate and minute; they constitute the greatest part of the semen, or sperm. They are peculiar shaped bodies, having a head, body, and tail, as illustrated in the accompanying figure, and they can only be seen by powerful magnifying glasses. (Fig. 1.) ~FIG. 1. At the left are six spermatozoa, or male-elements, male germ-cells. At the right is an ovum, egg, female germ-cell. All highly magnified.~ They have the remarkable property of moving about with considerable activity, and their number is almost beyond computation. =Only One Male Element Necessary.=--Although this number is so vast, yet only a single one is required to endow the female cell, or egg, with life. It is another illustration of how nature does everything possible to increase the chances of perpetuating the race, for without such immense numbers, the chances of the female egg being fertilized would be much less. =May Live for Days.=--Although these male elements can live but a few hours outside of the body, even when especial precautions are taken to make every thing favorable to their existence, yet they have been known to maintain their full life in the vaginal canal for more than eight days after their discharge; another remarkable provision of nature, for the prolonged existence of these cells increases the probability of the fertilization of an egg, and thus increases the chances of producing a new life. =The Female Element.=--As I have already said, the female germ-cell is also known as the ovum, or egg. A single ovum is shown in Fig. 1. If not fertilized by the male elements, the egg passes off into the outside world; if fertilized, it stops in the cavity of the uterus, where it forms an attachment. Here it remains until perfectly developed, when, at the end of nine months, it is brought forth to the outside world as a perfect infant.