The urethra having been laid open as far as it is deemed requisite to admit the passage of the stone, an exploration with the finger should be made. While the left forefinger, already in the bladder, explores the neck of the organ, the right hand, acting through the rectum, will, as far as possible, force the bladder backward in order to bring a larger area of surface within reach of the finger. Here a long index finger offers a distinct advantage, and should the operator fall short in this particular, he may take advantage of such help as his most practical assistant may be able to afford him. As a rule we are only capable of manipulating the neck and parts immediately beyond it, but by means of the short metallic sound, presently to be described, we are enabled to recognize any marked alteration in the naturally smooth, satin-like surface of the lining membrane. By careful exploration we may, for example, satisfy ourselves of the existence of tumour, false membrane, calcareous encrustation of the mucous layer so often found in association with calculous disorder. A knowledge of the presence or absence of these morbid conditions constitutes a distinct advantage in estimating the immediate success of the operation and prospective result of after-treatment.