Our knowledge of the individual and racial variations of the external sexual organs is still extremely imperfect. A few monographs and collections of data on isolated points may be found in more or less inaccessible publications. As regards women, Ploss and Bartels have devoted a chapter to the sexual organs of women which extends to a hundred pages, but remains scanty and fragmentary. (_Das Weib_, vol. i, Chapter VI.) The most systematic series of observations have been made in the case of the various kinds of degenerates--idiots, the insane, criminals, etc.--but it would be obviously unsafe to rely too absolutely on such investigations for our knowledge of the sexual organs of the ordinary population. There can be no doubt, however, that the external sexual organs in normal men and women exhibit a peculiarly wide range of variation. This is indicated not only by the unsystematic results attained by experienced observers, but also by more systematic studies. Thus Herman has shown by detailed measurements that there are great normal variations in the conformation of the parts that form the floor of the female pelvis. He found that the projection of the pelvic floor varied from nothing to as much as two inches, and that in healthy women who had borne no children the distance between the coccyx and anus, the length of the perineum, the distance between the fourchette and the symphysis pubis, and the length of the vagina are subject to wide variations. (_Lancet_, October 12, 1889.) Even the female urethral opening varies very greatly, as has been shown by Bergh, who investigated it in nearly 700 women and reproduces the various shapes found; while most usually (in about a third of the cases observed), a longitudinal slit, it may be cross-shaped, star-shaped, crescentic, etc.; and while sometimes very small, in about 6 per cent. of the cases it admitted the tip of the little finger. (Bergh, _Monatsheft für Praktische Dermatologie_, 15 Sept., 1897.) As regards both sexes, Stanley Hall states that "Dr. F.N. Seerley, who has examined over 2000 normal young men as well as many young women, tells me that in his opinion individual variations in these parts are much greater even than those of face and form, and that the range of adult and apparently normal size and proportion, as well as function, and of both the age and order of development, not only of each of the several parts themselves, but of all their immediate annexes, and in females as well as males, is far greater than has been recognized by any writer. This fact is the basis of the anxieties and fears of morphological abnormality so frequent during adolescence." (G.S. Hall, _Adolescence_, vol. i, p. 414).