was commissioned Hospital Assistant on 24 June 1815, after having studied for a year under John Abernethy at St Bartholomew's Hospital in London. He was sent immediately to Belgium to attend the wounded from the Battle of Waterloo and returned two weeks later with the first batch of wounded aboard a hospital ship; during the voyage he successfully employed Abernethy's technique of leaving wounds open to the air. His army work at the Brussels military hospital (near Waterloo) impressed upon him the need for a comprehensive training in anatomy if surgery were to be successful. Knox was intelligent, critical and irritable. He did not suffer fools gladly and—in an aside with terrible consequences for his future career—he was critical of the surgical work of Charles Bell with casualties at the Battle of Waterloo. After a further trip to Belgium he was placed in charge of Hilsea hospital near Portsmouth, where he experimented with non-mercurial cures for syphilis. In April 1817, he joined the 72nd Highlanders and sailed with them to South Africa. There were few army surgeons in the Cape Colony but Knox found the people healthy and his duties were light. He enjoyed riding, shooting and the beauty of the landscape with which he felt in spiritual harmony—an early expression of his transcendental world view. Knox developed an interest in observing racial types, and disapproved of what he saw as the Boers' contempt for the indigenous peoples. However, after an abortive Xhosa rebellion against the colonial forces, he was involved in a retaliatory raid commanded by Andries Stockenström, a magistrate and future Lieutenant Governor. Relations with Stockenström were marred when Knox accused O. G. Stockenström, Andries' brother, of theft, a charge apparently prompted by ill feeling between British and Boer officers. A court martial acquitted O. G. of the charge and Andries called Knox's conduct shameful. One of Stockenström's supporters, a former naval officer named Burdett, challenged Knox to a duel. Knox initially refused to fight, and Burdett "soundly horse whipped him on the parade before every Officer of the Garrison." Knox then grabbed a sabre and inflicted a slight wound to Burdett's arm. Knox's promotion to Assistant Surgeon was cancelled and he returned to Britain in disgrace, arriving on Christmas Day 1820. He remained only until the following October, after which he went to Paris to study anatomy for just over a year (1821–22). It was then that