Let us turn to the supposed influence of masturbation in causing insanity and nervous diseases. Here we may chiefly realize the immense influence exerted on medical science by Tissot and his followers during a hundred years. Mental weakness is the cause and not the result of excessive masturbation, Gall declared,[320] but he was a man of genius, in isolation. Sir William Ellis, an alienist of considerable reputation at the beginning of the last century, could write with scientific equanimity: "I have no hesitation in saying that, in a very large number of patients in all public asylums, the disease may be attributed to that cause." He does, indeed, admit that it may be only a symptom sometimes, but goes on to assert that masturbation "has not hitherto been exhibited in the awful light in which it deserves to be shown," and that "in by far the greater number of cases" it is the true cause of dementia.[321] Esquirol lent his name and influence to a similar view of the pernicious influence of masturbation. Throughout the century, even down to the present day, this point of view has been traditionally preserved in a modified form. In apparent ignorance of the enormous prevalence of masturbation, and without, so far as can be seen, any attempt to distinguish between cause and effect or to eliminate the hereditary neuropathic element, many alienists have set down a large proportion of cases of insanity, idiocy, epilepsy, and disease of the spinal cord to uncomplicated masturbation. Thus, at the Matteawan State Hospital (New York) for criminal lunatics and insane prisoners, from 1875 to 1907, masturbation was the sole assigned cause of insanity in 160 men (out of 2,595); while, according to Dr. Clara Barrus, among 121 cases of insanity in young women, masturbation is the cause in ten cases.[322] It is unnecessary to multiply examples, for this traditional tendency is familiar to all.