One of the most efficient of all methods of treatment is the use of the conical steel sound, as large as the urethra will admit without violence. The sound should be warmed, lubricated, and gently carried into the bladder at intervals of two to four days. The daily passage of the sound is objectionable, even if it gives relief at first, for it is liable to kindle a slow inflammation in a urethra unaccustomed to its use. When a sound is inserted it should not be left an instant in the bladder, but should be gently withdrawn as soon as it has been fully inserted. If left in the urethra, it does no good, and may act upon the cut-off group of muscles in the membranous urethra, causing them to contract spasmodically, as in the physiological performance of the coup-de-piston after urination. Such contraction bruises the sensitive mucous membrane of the urethra against the hard sound, and does mechanical damage. The sound acts in three ways: It (1) mechanically distends the irritable contracted cut-off muscle and seems to quiet its contractile tendency. It (2) squeezes all the blood from the passively congested vessels of the irritated mucous membrane, thus ensuring a new supply of blood to the part and an improved circulation in the reaction which follows the irritation. It (3) mechanically, by contact, blunts the sensibility of the terminal sensitive nerves in the mucous membrane of the deep urethra. In this way the sound acts, and its effects generally last several days, often a week. Its good effect is also instantaneous. The slight feeling of weight and discomfort in the perineum which the patient has before its use is gone instantly, and replaced by a feeling of comfort. When this immediate sense of relief is not experienced, it is doubtful whether such a case will yield to the simple treatment by sounding.