[141] _Description of Sir Spencer Wells's Trocar._--"It consists of a hollow cylinder six inches long, and half an inch in diameter, within which another cylinder fitting it tightly plays. The inner one is cut off at its extremity, somewhat in the form of a pen, and is sharp. The sharp end is kept retracted within the outer cylinder by a spiral spring in the handle at the other end, but can be protruded by pressing on this handle when required for use. When thus protruded it is plunged into the cyst up to its middle; the pressure on the handle is taken off, and the cutting edge is retracted within its sheath. The fluid rushes into the tube, and escapes by an aperture in the side, to which an india-rubber tube is attached, the end of which drops into a bucket under the table. The instrument is furnished at its middle with two semicircular bars, carrying each four or five long curved teeth like a vulsellum. These teeth lie in contact with the outer surface of the cylinder, but can be raised from it by pressing two handles. When the cyst begins to be flaccid by the escape of the fluid, these side vulsellums are raised, and the adjoining part of the cyst is drawn up under the teeth, where it is firmly caught and compressed against the side of the tube." [142] For further details on the operations described above, reference may be made to Sir Spencer Wells's work on ovarian disease, and to the very valuable papers contributed by Dr. Thomas Keith to the _Edinburgh Medical Journal_. To the latter especially the author is indebted for much oral instruction, and for the opportunity of seeing his careful and dexterous mode of operating. [143] _Lect. on Surgery_, 3d ed., vol. ii. p. 998. [144] _Operative Surgery_, p. 462. [145] Rough diagram of abnormal course of obturator and its relation to the neck of a hernia. Parts seen from the inside: H, femoral hernia; A, femoral artery; V, femoral vein; E, epigastric artery; O, obturator from epigastric (dangerous); S O, obturator from epigastric (safe); N O, normal course of obturator; I R, internal inguinal ring; Sp C, spermatic chord and its vessels; G, Gimbernat's ligament; +, in triangle of Hesselbach. [146] Holmes's _Surgery_, 3d ed., 1883, vol. ii. p. 837. [147] _Clinical and Pathological Observations in India_, pp. 44, 325. [148] Wood _On Rupture_, 1863. [149] Diagram of an artificial anus, showing small sutures which unite the edges of the gut and the skin, and the large ones stitching up the wound beyond. CHAPTER XII. OPERATIONS ON PELVIS. LITHOTOMY.--However interesting and even instructive it might be, any history of the various operations for the removal of calculi from the bladder would be quite out of place in a manual such as this. It will be sufficient here to describe the operations recommended and practised in the present day. There are three different situations in which the bladder may be entered for the purpose of removing a calculus:--