Prevention Better than Cure.--We might mention numerous other diseased conditions which grow out of inattention to the laws of health relating to the sexual organism; but to dwell longer upon this part of the subject would be to depart from the plan of this work, and we must forbear. This whole class of maladies is noted for obstinacy in great numbers of cases when the morbid conditions have existed for a long time. In addition it should be remarked that some of the most inveterate disorders of the nervous system originate in this same manner. The thousands of ladies who are suffering with spinal irritation, organic disease of the spine and other nervous disorders, are witnesses to this fact. It is apparent, then, that prevention of these serious maladies by attention to sexual hygiene, especially to the hygiene of menstruation at the first establishment of that function, is a matter of gravest importance. In fact, attention to hygiene is about all that is required. With this, drugs will be rarely required; without, they will be utterly useless. Extra-Uterine Pregnancy.--Sometimes the ovum becomes fecundated before reaching the uterus, and, instead of passing onward into that organ as usual, remains in its position in the Fallopian tube or even on the surface of the ovary. Occasionally an ovum falls into the cavity of the abdomen instead of passing into the tube. Even in this situation it may be fecundated. Impregnated ova thus left in abnormal positions, undergo a greater or lesser degree of development. They commonly result in the death of the mother. Twins.--The human female usually matures but one ovum at each menstrual period, the two ovaries acting alternately. Occasionally two ova are matured at once. If fecundation occurs, the result will be a development of two embryos at the same time. In rare cases, three or even four ova are matured at once, and by fecundation produce a corresponding number of embryos. As many as five children have been born alive at one birth, but have not lived more than a few minutes. The occurrence of multiple pregnancies may be explained by the supposition that ova matured subsequent to the first fecundation are also fecundated.