Stone, the common, name of calculus in the urinary bladder, for the composition of which see Calculi and Gravel. The prominent symptoms are irritability of the bladder with frequent irresistible desire to pass water, and occasional stoppage of the stream, with pain in various parts of the urinary system, and sometimes the presence of blood, mucus, and pus in the urine. None of these, however, can be depended on, the only sure diagnosis resting on making the stone perceptible to the ear and fingers by means of a metallic sound introduced through the urethra, and brought into direct contact with the foreign body; even with this instrument, several introductions in various positions of the body are sometimes necessary for its detection. The symptoms vary in intensity according to the size and roughness of the stone, the state of the urine, and the condition of the bladder. Stone is formed by a precipitation of the urinary salts either in the kidney, passing thence to the bladder, or primarily in the bladder. In the latter case a foreign body may be the nucleus.

Stone may be removed from the bladder by - 1, solution; 2, extraction as a whole through the urethra; 3, extraction through an opening artificially made into the bladder (lithotomy); 4, crushing into fragments of such a size that they can pass through the urethra (lithotripsy). 1. Solution may be attempted by remedies taken by the mouth or injected into the bladder. Uric acid calculi have been treated by the administration of alkalies, and the phosphatic by the injection of a solution of nitric acid. These methods have from their inefiicacy fallen into disuse. 2. Extraction by the urethra is now done only in females; in them the canal is so short and dilatable that a stone of considerable size can be removed by this method. 3. Lithotomy is indicated in all males under puberty, and in others when the stone is large or there are several; when the urethra is stric-tured; when the bladder is in such a condition as to bo unable to bear the repeated introduction of instruments, and the irritation caused by the fragments resulting from lithotripsy; and when the kidneys are not much diseased.

The operation may be done by incision above the pubes (the supra-pubic), through the perineum (the perineal), or through the rectum, or rectum and perineum (the recto-ves-ical). The supra-pubic and that through the rectum and perineum are usually employed only in cases in which, from the size of the stone or other causes, removal through the perineum is impossible. The perineal operations are three in number, the lateral, bilateral, and median. The lateral operation is in general the best, and it may be performed as follows : A grooved steel staff or sound of full size is introduced, the bladder being moderately distended, the patient on his back, with shoulders elevated, thighs separated widely in order to expose the perineum, and the hand grasping and bound to the foot; the patient being etherized, an incision is made on the left side of the perineum from about an inch before the anus downward and outward to a point midway between the anal opening and the tuberosity of the ischium, the muscular fibres being divided down to the staff; the left index finger passed into the wound keeps back the rectum, and at the same time feels at the membranous part of the urethra the groove, which is entered by the knife and conducts it to the bladder, the urethra and about half an inch of the prostate being divided; the finger is then introduced, dilating the opening; the finger being withdrawn, the forceps are introduced, opened, and the stone seized, if possible, with the first gush of fluid from the wound, and then extracted by slow, steady, and undulating movements, dilating and not tearing the soft parts.

If properly performed, and the after treatment not interfered with by haemorrhage, inflammation, sloughing, or other complications, the urine begins to flow by the urethra in about a week, and the wound heals completely in four or five weeks. In the bilateral operation, a curved incision, with the convexity upward, is made from one side of the perineum to the other, between the anus and the urethral bulb, dividing both sides of the prostate by a double bistoury. The median operation differs from the preceding in that the incision is vertical and in the median line, and the prostate is not cut, but is dilated, and somewhat lacerated, by the finger introduced through the opening made into the urethra in front. The recto-vesical operation consists in cutting into the bladder from the rectum on the median line behind the prostate, or in dividing also the prostate and perineum in the median line. In the high operation the bladder is opened above the pubes through the linea alba, where there is no covering of peritoneum.

Lithotomy was practised 25 centuries ago; Hippocrates bound his pupils by oath not to practise it, but it came into use again in the time of Celsus, in whose writings are found the first indications of the bilateral operation; the lateral operation was first practised toward the end of the 17th century; the supra-pubic method was first employed by Franco in the 16th century, and the rectovesical by Sanson in the 19th. 4. Lithotripsy (more commonly called lithotrity) is indicated in patients beyond puberty, when the stone is single and not large, and when the urethra is not strictured, and the bladder and kidneys are not much diseased. The early instruments used for this purpose were very rude and dangerous, the stone being grasped by branches made to protrude from a straight catheter, and then bored by a drill extending through the instrument and worked by a watchmaker's bow; after it was bored it was crushed by another complicated instrument. To Civiale (1817-'24) is unquestionably due the credit of having introduced the operation by improving the instruments and the manner of their use.

The instrument now used is composed of two sliding blades, introduced in the shape and after the manner of a sound, between which the stone is seized, and then crushed by the gradual pressure of a screw; the fragments may then be washed out by injections or by the urine, large pieces being again broken by the same or a smaller instrument. In properly selected cases, and with skilful manipulation, this operation is much safer than lithotomy.