Much of the renown acquired for Kentucky by her surgeons was in the treatment of calculous diseases. This State is believed to have furnished almost as many cases of stone as all the rest of the Union. Dr. Dudley stands the confessed leader of American lithotomists, heading the list with two hundred and twenty-five cases. Of these he presents an unbroken series of one hundred consecutive successful operations. He used the gorget in all. He preferred the instrument invented by Mr. Cline, of London. "In one case, when his patient was on the table, he discovered that his accustomed operation was impracticable from deformity of the pelvis, and while his assistants were taking their positions resolved to make the external incision transverse, which was executed before any one else present had remarked the difficulty." Through this incision he removed a stone three and a half inches in the long diameter, two and a half inches in the short, by eleven inches in circumference. The patient recovered. In an article contributed to the Transylvania Journal of Medicine by Dr. Dudley, in 1828, he thus wrote of the trephine: "The experience which time and circumstances have afforded me in injuries of the head induced me to depart from the commonly received principles by which surgeons are governed in the use of the trephine. In skillful hands the operation, beyond the atmosphere of large cities, is neither dangerous in its consequences nor difficult in the execution." In this remark Dr. Dudley bore early testimony to the efficacy of aseptic surgery. He urged the trephine in the treatment of epilepsy and applied it in six cases--in four of which the disease was cured. The result in the two remaining cases is unknown, because the patients were lost sight of. Dr. Dudley believed himself to be the first surgeon who ever attempted to treat _fungus cerebri_ by gentle and sustained pressure made with dry sponge aided by the roller. Of the first cases in which he used it, he wrote: "By imbibing the secretions of the part, the pressure on the protruded brain regularly and insensibly increased until the sponge became completely saturated. On removing it the decisive influence and efficacy of the agent remained no longer a matter of doubt." He noted the difficulty experienced in removing the sponge because of its being extensively penetrated by blood-vessels springing from the surface of the brain. This inconvenience he afterward obviated by putting a thin piece of muslin between the fungus and the sponge. He saw in this property of the sponge what no doubt others had seen before, the phenomenon of sponge-grafting, but like them he failed to utilize it in practice.