(_a._) Attempts to plug the canal have, in most cases, been made by invagination of the skin of the scrotum and its fascia. These have been very numerous and various in their adaptation of mechanical appliances, but have all been designed with the same object. Dzondi of Halle, and Jameson of Baltimore, incised lancet-shaped flaps of skin, and endeavoured to fix them by displacement over the ring. Gerdy invaginated a portion of scrotum and fascia into the enlarged canal, by the forefinger pushed it up, and secured it in its place by a thread passed from the point of his finger first through the invaginated skin, then through the abdominal walls, endeavouring to include the walls of the inguinal canal, causing the point of the needle to project some lines above the inguinal ring; the same process being effected with the other end of the thread on the other side of the finger, and the two ends which have been brought out near each other on the abdominal wall, being tied tightly over a cylinder of plaster. The ensheathed sac was then painted with caustic ammonia to excite inflammation, and a pad put on over all. Signoroni modified this by fixing the invaginated skin by a piece of female catheter, retained in its place by transfixion by three harelip needles, tied by twisted sutures. Wützer of Bonn, again, modified this, by substituting a complicated instrument, consisting of a stout plug in the inguinal canal, held in position by needles which are passed through the anterior wall of the canal in the groin. Compression between plug and compress, with the intention of causing adhesion between skin, fascia, and sac, is then managed by means of a screw. The plug is retained for about seven days. Modifications of this method have been tried by Wells, Rothmund, and Redfern Davies, all aiming in the direction of simplicity; but by far the most simple and efficacious method on the Wützer principle yet devised is that of Professor Syme, which he described in the pages of the _Edinburgh Medical Journal_ for May 1861, in which the invagination of integument is both simply and securely managed by strong threads, as in Gerdy's method, while a piece of bougie or gutta-percha, to which the threads are fixed, replaces Wützer's expensive and complicated apparatus. Sir J. Fayrer of Calcutta has had a very large experience of Wützer's method, and also of a plan of his own. Out of 102 cases by the latter method, 77 were cured, 9 relieved, 14 failed, and 2 died.[147] Mr. Pritchard of Bristol has proposed an additional step in operations on the invagination principle, consisting in the stripping of a thin slip of skin from the orifice of the cutaneous canal, and then putting a pin through the parts to get them to unite, and thus close the aperture completely.