Adams,[15] in 1812, revived the operation of Cheselden with certain modifications. While his puncture was made in the same location, his technic was different. He entered the sclera with a small iris-scalpel[5] of his own special design (Fig. 7), which, like Sharpe, he passed through the iris-membrane into the anterior chamber, carrying it across to the nasal side (Fig. 8). From entrance to exit he always kept the edge of the knife turned back toward the iris, so as to cut from before backward. He was thus able by the most delicate pressure of his instrument, to make a long horizontal incision, without causing iridodialysis (Fig. 9). If the first incision appeared to be too short, he did not withdraw the knife entirely, but again carried it forward and partially withdrew it, always cutting in the same plane. To quote his own words, “by repeating the efforts to divide the iris (taking care in so doing to make as slight a degree of pressure as possible upon the instrument, instead of withdrawing it out of the eye at once, as recommended by Cheselden), a division of that membrane may, in almost all cases be effected, of a requisite size to establish a permanent artificial pupil” (Figs. 10 and 11). [15] Adams, Sir William: A Treatise on Artificial Pupil, London, 1819, p. 34, et seq. [Illustration: Fig. 8.--Adams’ iris scalpel in situ, showing location of scleral puncture (after Lawrence).] [Illustration: Fig. 9.--Iridotomy by Adams’ method (after Lawrence).] [Illustration: Fig. 10.--Occlusion of pupil (Adams).] [Illustration: Fig. 11.--The resulting pupil after iridotomy (Adams).] Here were three elements of success, a sharp knife, a gentle sawing movement, and the most delicate pressure of the instrument. His method was a decided advance, and he reported success in nearly one hundred cases. Others, less skilful, however, failed of success, and the severe criticisms of Scarpa,[16] though evidently unjust and tinged by personal animosity,[17] cast a shadow of doubt on the method. [16] Scarpa, Antonio: Trattato Delle Principali Malattie Degli Occhi, Ed. quinta, l’avia, 1816, translated by James Briggs, London, 1818, p. 373. [17] Edin. Med. and Surg. Jour., No. 58. [Illustration: Fig. 13.--Iris-knife in position to make central pupil (Walton, after Beer).]