If the sound passes, without hinderance, the last situation, but with increased pain, the membrane of that part is diseased, and may extend to the bladder; which will be indicated by the frequent desire to micturate during the night, owing to the irritable state of that organ. If the instrument be arrested at about six inches and a half, the complaint, in all probability, is seated in the transverse portion of the prostate, and requires very cautious treatment. When the obstruction is at the very entrance of the bladder, a resistance will be perceived, which, on yielding, will impart a peculiar sensation as the sound enters the bladder. When stricture is thus situated, there is a frequent desire, with almost total inability, to micturate; and when once formed, it is productive of the most serious mischief, unless relieved. In cases of permanent stricture, the passing of the sound conveys the sensation of going over a ridge. Where it meets with a temporary stoppage, and then passes on, it has probably hitched to a fold of the urethra. Sometimes it will enter the orifice of a dilated follicle; and if much pressure is used, it will occasion considerable bleeding. The nature and situation of the disease being ascertained, the cure may now be proceeded in, recollecting that no force is to be used, and that too much be not attempted at one essay. Now without entering into an inquiry as to the laws on which _contraction_ and _elasticity_ of certain animal structures depend, it is enough for our purpose to know, that the urethra possesses both properties; it may contract so as to oppose the exit or entrance of the smallest stream, and it may be dilated to admit the introduction of an instrument an inch in circumference. The urethra maintains these properties in disease as well as in health, and upon the strength of this fact, is the practice of dilatation in the cure of permanent stricture founded, permanent stricture, it will be recollected, is a positive narrowing of the urethric canal; and as it is the nature of all organic diseases to progress, unless prevented by art, it needs no stronger argument than necessity to show how imperative it is to set about their removal. The cure by dilatation is as follows:—the seat and size of the stricture being ascertained (both of which can be easily done by the passing of the sound as directed, and the observance of the stream of urine), a bougie in circumference somewhat larger than the calibre of the urinary current, warmed and dipped in an oleaginous mixture combined with some sedative (Forms 22, 23, 24) or stimulant (Form 25) according to circumstances, is to be passed to the stricture, and the gentlest pressure is to be employed for the space of five, ten, or twelve minutes, according to the irritation it produces, removing it as soon as any uneasiness is felt.