The staff is next introduced and the stone felt; if there is little water in the bladder a few ounces may be injected, but this is rarely necessary, for the patient should be ordered to retain as much water as possible, and when he cannot retain it, injection of water may do harm, and will probably not be retained, but at once come away along the groove in the staff. The staff is then committed to a special assistant, who must be thoroughly up to his duty, and attend to the staff alone.

Some surgeons direct the assistant to make the convexity of the staff bulge in the perineum, to enable the groove to be struck more easily. It will be, however, safer both for the rectum and the bulb, if the staff be hooked firmly up against the symphysis pubis, as advised by Liston. The same assistant can also keep the scrotum up out of the way.

If the perineum has not been previously shaved, this is now done.

The operator sits down on a low stool in front of the patient's breech, his instruments being ready to his hand, and then steadying the skin of the perineum with the fingers of his left hand, enters the point of the knife in the raphe of the perineum, midway between the anus and scrotum (one inch in front of anus—Cheselden, Crichton; one and a quarter—Gross, Skey, and Brodie; one and three-quarters—Fergusson; one inch behind the scrotum—Liston), and carries the incision obliquely downwards and outwards, in a line midway between the anus and tuberosity of the ischium. The length of the incision must vary with the size of the perineum, and the supposed size of the stone, but there is less risk in its being too large, so long as the rectum is safe, than in its being too small. Its depth should be greatest at its upper angle, where it has to divide the parts to the depth of the transverse muscle of the perineum, and least at its lower angle, where a deep incision is not required, and would be almost sure to wound the rectum.

The forefinger of the left hand is now to be deeply inserted into the wound, and any remaining fibres of the levator ani in front are to be divided, the edge of the knife being directed from above downwards. The left forefinger being still used to push its way through the cellular tissue, the groove in the staff is now felt in the membranous portion of the urethra covered by the deep fascia of the perineum. Now comes the deeper part of the incision. Guided by the finger-nail of the left hand, the surgeon introduces the point of the knife into the groove of the staff. He then takes hold of the staff for a moment to feel that it is held up properly against the pubis, and in the middle line, and also that the knife is fairly in the groove. Giving the staff back again to the assistant, and keeping the rectum well out of the way by the left hand, he now steadily directs the knife along the groove of the staff till the bladder is fairly entered, and the ring at the base of the prostate completely divided. When this is the case a gush of urine takes place, following the withdrawal of the knife.

When making the deep incision, and in the groove of the staff, the blade of the knife should lie neither vertical nor horizontal, but midway between the two, so as to make the section of the left lobe of the prostate in its longest diameter, that is, in a direction downwards and backwards (Fig. xxxiv. L).

The knife is now withdrawn, and the left forefinger inserted. In most cases it will be long enough to reach the bladder and touch the stone, and may then be freely used by gradual pressure to dilate the wound; this may be done very freely when necessary for a large stone, if only the ring of fibrous tissue surrounding the urethra be first cut and the bladder fairly entered. Whenever the stone is felt by the finger, the assistant may withdraw the staff.

When the operator has thus felt the stone and sufficiently dilated the wound, the next step is to introduce the forceps; this should be done under the guidance of the finger, and with the blades closed. When the stone is felt the blades should be opened very widely, slightly withdrawn, and then pushed in again, the lower one, if possible, being insinuated under the stone. The blades must be made fairly to grasp and contain the stone in their hollow, for if they only nibble at the end of an oval stone, extraction is impossible. Extraction should then be performed slowly, with alternate wrigglings of the forceps from side to side, so as gradually to dilate, not to tear, the prostate, and the operator must remember to pull in the axis of the pelvis, not against the os pubis or the promontory of the sacrum.

If there is much resistance, it may possibly be caused by the stone having been caught in its longer axis, and this may be remedied by careful manipulation by means of the finger and forceps. If the stone is still too large to be extracted without greater force than is warrantable, there are still various expedients (see infra, pp. 265, 270).

In most cases, however, the stone is removed rapidly enough by the single incision. The finger, or a sound, must then be introduced to feel if any more stones are present. The closed forceps make a very effectual instrument for this purpose. Much information may be gained from the appearance of the first stone, the presence or absence of facets. Its smoothness or roughness enables us to form a pretty certain opinion; yet the bladder should always be carefully searched; and if the stone has been friable or broken in extraction, should be washed out by a current of water. Where the calculi are very numerous, or where many fragments have separated, the scoop will be found useful, both for detecting and removing them. All the stones being extracted, there is in most cases little or no bleeding (see infra, Hæmorrhage). The tube already described may now be inserted and tied into the bladder. It may be retained for forty-eight or seventy-two hours, according to circumstances. Care must be taken lest it be closed up by coagula during the first hour or two after the operation. In children the tube is not necessary, and from their restlessness might possibly do harm, but in adults (though neglected by some surgeons) experience shows it is a valuable adjunct in the after-treatment.