As a lecturer and teacher Simpson succeeded as in the other branches of his work. His brilliant exposition of his subjects and his careful practical manner of teaching his young listeners doubled the fame which had begun with his predecessor, Professor Hamilton, and has ever since belonged to the Edinburgh school of obstetricians. But here again his personal attractiveness and power gained for him the greater part of his success. In the words of the _Lancet_, written when reviewing a posthumous collection of some of his writings, his lectures used to brighten the gloomy days of the Edinburgh winter; in perusing the publication under review, Edinburgh men would "almost think they saw the big head and face of the great obstetrician, as they used to see him beaming with satisfaction or twinkling with genial humour as he told a good story, or related a happy case, illustrative of his own bold and original practice." Both as a lecturer and as a bedside teacher he captured his students by the charm of his diction, the wide range of his knowledge, and as Professor Gusserow has pointed out in his masterly memoir, by his peculiar talent of having his knowledge at his fingers' ends, and that often in very remote details. Year by year he never failed to obtain the affection of his students; scarcely a man that had been taught by him but would proudly boast that he was his friend as well as his teacher. He treated his large class in a confiding spirit--not as the superior person delivering _ex cathedra_ utterances, but as the friend rejoicing in his function of admitting those around him into the knowledge in which he seemed to revel. He had a happy method of getting on good terms with his audience before proceeding to the serious business of the lecture. When his health began to fail he was sometimes unwillingly laid aside, and the lectures were delivered by a substitute. On one occasion he re-appeared pale, weak, and lame, after such an enforced holiday, and was greeted enthusiastically by a crowded class. He told them that his servant had said to him that a rumour was abroad that he was in Morningside Asylum. He had asked what answer he had made, and heard that he had replied that so far from being wrong in his mind his master was writing a book in bed. While he did not say that this answer was strictly correct, he was happy to assure them, his pupils, that he was quite right in his mind, although a friend had hinted that morning that he was rather weak in his _understanding_! Old fellow-students meeting each other in after life as staid practitioners take pleasure in recalling the idiosyncrasies and peculiarities of their teachers; it is probable that no professor has ever been talked over with the appreciation which breathes through the reminiscences of Simpson conjured up by those whom he taught.