Not infrequently the affection subsides into the chronic form and the abscess, having a restricted channel for evacuation, remains as a suppurating cavity. _Diagnosis._ The enlargement and tenderness of the prostate as felt on rectal examination is pathognomonic. If the body of the urine is clear there is further corroboration, as in cystitis it is more or less turbid and flocculent or even bloodstained. Micturition is likely to be much more frequent in cystitis than in prostatitis. Catheterization is much more painful when the catheter passes the prostate in prostatitis than in cystitis. _Prognosis_ is always grave. Some cases recover completely, while others run on to a fatal termination, and still others merge into the chronic form. Cases that are complicated by abscess are always to be dreaded, as chronic suppuration, or pelvic or peritoneal infection, or pyæmia, or septic poisoning is liable to supervene. As the disease is more common in the old so it is liable to prove more severe and redoubtable. _Treatment._ In acute cases active derivation toward the bowels is desirable. A mercurial purge (calomel—horse or bull 1 to 2 drs.; dog, 2 to 5 grs.) may be followed a few hours later by salines (sodium sulphate—horse or bull 1 lb.; dog 1 oz.). Sodium sulphate or magnesium sulphate may also be given with glycerine as an enema. Great benefit may often be obtained from the application of leeches on the perineum or around the anus. The diet must be restricted and non-stimulating, mainly of amylaceous materials, and with the water, flaxseed tea may be liberally mixed. When the suffering is severe it may be met by camphor, camphor bromide, ergot, hamamelis, gelsemium or potassium bromide, given by the mouth or rectum. With violent strangury, opium, belladonna or hyoscyamus may be used. Some cases may be relieved by the use of enemata of cold water or pieces of ice in the rectum. In retention of urine, careful catheterization is imperative, the hand or finger in the rectum being employed to guide the point of the catheter under the prostate.