The ova are produced by the ovaries (the word ovaries means egg producers) where they slowly develop from cells which originate in these glands. When they have reached maturity, or are ready for fertilization, they pass out of the ovaries and down into the womb, by way of the fallopian tubes. As already stated, such passage of the ova from the ovaries into the womb occurs every twenty-eight days, and it is accomplished by a more or less copious flow of blood, a sort of hemorrhage, which carries the ova down through the fallopian tubes, and deposits them in the womb. This blood, after performing its mission of carrying the ova down into the womb, escapes from the body through the vaginal passage and is cared for by the wearing of a bandage between the thighs. This flow of blood continues for about five days, and is known as a menstrual flow; and this time in a woman's life is known as the menstrual period. It is so named because of the regularity of its recurrence, the word _mensa_ meaning a _month_. In common parlance, these periods are often spoke of as the "monthlies." After the ovum has reached the womb it remains there for a period of about ten days, after which, if it is not fertilized during that time, it passes out of the womb into the vaginal passage, and so out of the body. But if, at any time after it is ripe for fertilization, that is, from the time it begins its journey from the ovaries to the womb, and while it is in the womb, the ovum is met by the male sperm, it is _liable_ to become fertilized--conception is possible. These are facts of the _utmost importance_, to be thoroughly understood and kept well in mind by all married people who would live happily together, as will be hereafter shown. So much regarding the female part of the meeting of the ovum and the sperm. The male part of this mutual act is as follows: The sperm, or spermatozoa, originate in the testicles. Each sperm is an individual entity and _several thousands_ of them are produced and in readiness for use, _at each meeting_ of the male and female generative organs; and if _any one_ of the countless number comes in contact with the unfertilized ovum in the womb, conception is _liable_ to result. These sperms are so small that they are not visible to the naked eye, but they are readily seen by the use of a microscope. In shape they much resemble tad-poles in their earliest stages. At the base of the penis, well up in the man's body, there is a large gland which surrounds the penis like a thick ring, and which is called the prostate gland. It secretes a mucous fluid which looks much like, and is about the consistency of the white of an egg. Close to this gland, and almost a part of it, is a sack, or pocket, into which the mucous secretion from the prostate gland is poured, and where it is kept, ready for use, in performing its part of the germinal act.