Books almost without number have been written upon the subject treated in this work. Unfortunately, most of these works are utterly unreliable, being filled with gross misrepresentations and exaggerations, and being designed as advertising mediums for ignorant and unscrupulous charlatans, or worse than worthless patent nostrums. To add to their power for evil, many of them abound with pictorial illustrations which are in no way conducive to virtue or morality, but rather stimulate the animal propensities and excite lewd imaginations. Books of this character are usually widely circulated; and their pernicious influence is fully as great as that of works of a more grossly obscene character. In most of the few instances in which the evident motive of the author is not of an unworthy character, the manner of presenting the subject is unfortunately such that it more frequently than otherwise has a strong tendency in a direction exactly the opposite of that intended and desired. The writer of this work has endeavored to avoid the latter evil by adopting a style of presentation quite different from that generally pursued. Instead of restricting the reader's attention rigidly to the sexual function in man, his mind is diverted by frequent references to corresponding functions in lower animals and in the vegetable kingdom. By this means, not only is an additional fund of information imparted, but the sexual function in man is divested of its sensuality. It is viewed as a fact of natural history, and is associated with the innocence of animal life and the chaste loveliness of flowers. Thus the subject comes to be regarded from a purely physiological standpoint, and is liberated from the gross animal instinct which is the active cause of sensuality.