This manner of counting the dead and wounded has something specious in it, but it is defective in this respect, that it takes no account of what has escaped observation, and cannot be estimated. Every practitioner has undoubtedly seen more cases of masturbation than he has seen victims to this habit. But how many circumstances have prevented him from seeing all the diseases which are caused by this habit, or have prevented him from referring these diseases to their true cause? We have already mentioned the influence which his previous reading and occupation have on this subject; to this cause of errour, we may add others. How numerous are the affections which are borne in silence and which never come under the notice of a physician. How numerous too the practitioners who avoid the trouble of referring to the immediate or remote causes of the diseases which are observed by them, and who confine themselves simply to their treatment, without tracing them to their source. How often too are diseases resulting from onanism attributed to causes with which they have no connexion, to causes which were indicated by persons who knew no better, or even by the patient who believed himself to be interested in giving wrong statements. How frequently also does the practitioner exclude himself from obtaining information, by abstaining from making suggestions to the parents, which all hear with displeasure, and repel with indignation. How often, also, does he refrain from asking necessary questions, for fear of wounding the modesty of the young patient, of teaching him a thing of which perhaps he is ignorant, or at least of exciting in him a dangerous curiosity! Finally how frequently are his doubts removed by the art with which those who indulge in onanism, even when young, know how to conceal a habit at which they blush in secret. Now is it reasonable to expect, that the physician when surrounded by so many causes of errour, should go into statistical details and estimate from them the sum total of the ills produced by onanism and other excesses of a similar character? This method would undoubtedly lead to taking a part for the whole and consequently to forming too narrow an opinion of the evil. Many authors having followed this course, and having considered the evils which are unobserved by them as only imaginary, have not denied the dangers and inconveniences of venereal excesses, but have supposed that they exist less frequently than is really the case.