It is probably well within bounds to affirm that our present beliefs concerning normal sex life and average experience and practice have the status of surmises standing on foundations no more secure than general impressions and scattering personal histories. It is time we began building on collected case records running through lifetimes in series counted in tens of thousands. In view of the pervicacious gonad urge in human beings, it is not a little curious that science develops its sole timidity around about the pivotal point of the physiology of sex. Perhaps this avoidance—not of the bizarre and the extreme, the abnormal and the diseased, but of the normal usages and medial standards of mankind—perhaps this shyness is begotten by the certainty that such study cannot be freed from the warp of personal experience, the bias of individual prejudice, and, above all, from the implication of prurience. And yet a