The Ovaries, as already remarked, are two oval-shaped bodies, placed one on each side of the womb, and connected with it, whose use is to form the germ or rudiment, called the ovum, or egg, from which the new being is developed. The structure of the Ovaries is very simple, and the manner in which they produce the ovum is not very well understood. It is certain however, that they are indispensable to conception, being in fact the most essential parts of the female generative system. MENSTRUATION. Menstruation appears to be a process resulting from the development and healthy action of the Female organs, and is essential to their well being. The following brief account of its nature and origin is extracted from my _Diseases of Woman_, page 152 to 155: "Until very recently but little was known, with any certainty, respecting this remarkable and important phenomenon of the female system. The most crude and visionary theories have been advanced to explain it, and our works on medicine and physiology do nothing more than repeat them, one after the other. The investigations of several distinguished physiologists however, within the last few years, have thrown a new light on this hitherto obscure subject, and explained much that was previously unknown, or, at best, merely conjectured upon. A brief statement of the result of those investigations will not only be highly interesting in itself, but will materially assist in explaining what we shall afterwards speak upon. "It is well known that the female organs are liable, at regular periods, to assume a peculiar action, which results in the discharge of a fluid termed the menses. The secretion and excretion of which are highly essential, both to the proper performance of many other functions, and to the maintenance of the general health. Whence comes this fluid, and what causes it to flow? These were questions unanswered, except by mere supposition, previous to the discoveries referred to, which we now proceed to make known.