In 1815 Liston became surgeon’s clerk or house-surgeon in the Royal Infirmary of Edinburgh, in which capacity he availed himself fully of the opportunities for making _post mortem_ examinations, which were then performed by the house-surgeons. In 1816 he went to London, and studied several months at St. George’s Hospital, and also attended some of Abernethy’s lectures. In 1817, having taken the diplomas of the College of Surgeons both in London and Edinburgh, he began practice in Edinburgh, and again assisted Dr. Barclay in his anatomical teaching. But misunderstandings arising between them, Liston left Barclay and commenced to lecture on his own account at the beginning of the session 1818-19, James Syme becoming his assistant. In 1823 Liston gave up teaching anatomy in favour of Syme, in order to devote himself entirely to surgical teaching; but Liston retained a large share of the proceeds of the anatomical lectures, as the originator and more important proprietor of the joint school. This arrangement did not last long, Syme withdrawing to Brown Square in 1824: and it appears that Liston is, at least equally with Syme, open to the charge of having displayed serious jealousy in this matter. They were unavoidably serious rivals, too nearly equals in power, and perhaps too conscious of their own individual claims, to be able to view with equanimity each other’s proceedings and advancement. Liston had published a little book on the Surgical Anatomy of Crural Hernia (1819), and soon acquired fame by performing several brilliant operations, difficult amputations, ligatures of arteries, lithotomy, &c. At that time there were many defects in the management of the Royal Infirmary, and Liston set to work, young as he was, to agitate for their removal. Unfortunately he did not make any attempts to conciliate the managers in so doing, and his outspoken complaints were met with bitter opposition from some of the surgeons as well as managers. He entered into the spirit of controversy which Dr. Gregory had done so much to foment, and in which so much of the talent and time of Edinburgh men was then wasted. In 1821 Liston records that he was almost daily applied to by patients from the Infirmary who had failed to secure relief from the surgeons, and he was exposed to the charge of decoying patients thence. It was even demanded of him, on pain of perpetual exclusion from the surgeoncy to the Infirmary, that he should refuse his professional assistance to any person who had been a patient there. He naturally refused to comply with any such condition, nor would he absent himself from attendance on the Infirmary practice, as was also suggested. It is fair to say that Liston courted the fullest investigation of his actions, and denied that he had ever directly or indirectly insinuated to any patient of the Infirmary that the practice followed there was bad, or that he himself knew better, or had in any way tried to entice patients away.