Of the local causes referable to the genitalia, by far the most important and most frequent are hyperæsthesia and inflammation of the prostatic portion of the urethra, which are generally induced by masturbation. These lesions constitute the primary source of the trouble in the large majority of cases, and tend not only to excite reflex pollutions, but to maintain the disorder by keeping the mind occupied with sexual matters. Other common local causes are found in congenital narrowing of the meatus, organic stricture of the urethra, a redundant prepuce, balanitis, and the accumulation of smegma. Among the more infrequent etiological factors may be mentioned herpes of the prepuce, congenital shortness of the frenum, spasmodic stricture, polypus of the deep urethra, spermato-cystitis, and epididymitis. Among the remaining exciting causes of pollutions are diseases of the anus and rectum, as hemorrhoids, morbid growths, ascarides, fissures, ulcers, pruritus, and painful eruptions. The nerves of the rectum and anus being derived from the same region as those of the genitalia, it is not surprising that the ejaculatory centre should respond to an impulse transmitted from them. In habitual constipation straining at stool may also excite an emission through the consentaneous action of the muscles of the abdomen, rectum, and seminal vesicles; but this is only observed when the orifices of the ejaculatory ducts are paralyzed and patulous. ANATOMICAL CHARACTERS.--There are no records of the morbid appearances which appertain to seminal incontinence in its early stage, but that the hyperæsthesia of the prostatic urethra depends upon chronic or subacute inflammation is rendered certain by the concomitant symptoms, by exploration with the sound, aided by the finger in the rectum, and by the results of treatment. In the advanced stage, post-mortem inspection has disclosed stricture of the urethra, injection of the mucous membrane of the deep portion of the urethra, dilatation and excoriation of the orifices of the ejaculatory ducts, and suppuration of the prostate and the seminal vesicles. The changes which occur in the nervous centres are unknown.