We have written this chapter especially for girls, and we sincerely hope that many will read it with an earnest desire to be benefited by so doing. The subject of which we have to write is a delicate one, and one which, we regret exceedingly, needs to be written about. But our experience as a physician has proven to us again and again that it is of the utmost importance that something be said, that words of warning should be addressed particularly to the girls and maidens just emerging into womanhood, on a subject which vitally concerns not only their own future health and happiness, but the prosperity and destiny of the race. Probably no one can be better fitted to speak on this subject than the physician. A physician who has given careful attention to the health and the causes of ill-health of ladies, and who has had opportunities for observing the baneful influence exerted upon the bodies and minds of girls and young women by the evil practices of which it is our purpose here to speak, can better appreciate than can others the magnitude of the evil, and is better prepared to speak upon the subject understandingly and authoritatively. Gladly would we shun the task which has been pressed upon us, but which we have long avoided, were it not for the sense of the urgent need of its performance of which our professional experience has thoroughly convinced us. We cannot keep our lips closed when our eyes are witnesses to the fact that thousands of the fairest and best of our girls and maidens are being beguiled into everlasting ruin by a soul-destroying vice which works unseen, and often so insidiously that its results are unperceived until the work of ruin is complete. The nature of our subject necessitates that we should speak plainly, though delicately, and we shall endeavor to make our language comprehensible by any one old enough to be benefited by the perusal of this chapter. We desire that all who read these pages may receive lasting benefit by so doing. The subject is one upon which every girl ought to be informed, and to which she should give serious attention, at least sufficiently long to become intelligent concerning the evils and dangers to which girls are exposed from this source.