Kahlbaum, it is true, under the influence of the older tradition, when he erected katatonia into a separate disorder (not always accepted in later times), regarded prolonged and excessive masturbation as a chief cause, but I am not aware that he ever asserted that it was a sole and sufficient cause in a healthy organism. Kiernan, one of the earliest writers on katatonia, was careful to point out that masturbation was probably as much effect as cause of the morbid nervous condition.[327] Maudsley (in _Body and Mind_) recognized masturbation as a special exciting cause of a characteristic form of insanity; but he cautiously added: "Nevertheless, I think that self-abuse seldom, if ever, produces it without the co-operation of the insane neurosis."[328] Schüle also recognized a specific masturbatory insanity, but the general tendency to reject any such nosological form is becoming marked; Krafft-Ebing long since rejected it and Näcke decidedly opposes it. Kraepelin states that excessive masturbation can only occur in a dangerous degree in predisposed subjects; so, also, Forel and Löwenfeld, as at an earlier period, Trousseau.[329] It is true that Marro, in his admirable and detailed study of the normal and abnormal aspects of puberty, accepts a form of masturbatory insanity; but the only illustrative case he brings forward is a young man possessing various stigmata of degeneracy and the son of an alcoholic father; such a case tells us nothing regarding the results of simple masturbation.[330] Even Spitzka, who maintained several years ago the traditional views as to the terrible results of masturbation, and recognized a special "insanity of masturbation," stated his conclusions with a caution that undermined his position: "Self-abuse," he concluded, "to become a sole cause of insanity, must be begun early and carried very far. In persons of sound antecedents it rarely, under these circumstances, suffices to produce an actual vesania."[331] When we remember that there is no convincing evidence to show that masturbation is "begun early and carried very far" by "persons of sound antecedents," the significance of Spitzka's "typical psychosis of masturbation" is somewhat annulled. It is evident that these distinguished investigators, Marro and Spitzka, have been induced by tradition to take up a position which their own scientific consciences have compelled them practically to evacuate.