In 1848 Dr. Bennett was unanimously elected Professor of the Institutes of Medicine (_i.e._, Physiology) at Edinburgh. In this new work he was soon conspicuous for the practicality of his teaching, and for his continual introduction of matters bearing on pathology and medicine. He made every lecture a complete study, enriching it with all the appliances, material and artistic, that he could command, and embellishing it by finished elocution. He would now and again lay aside his manuscript to comment upon, and frequently to denounce, the opinions of others, by which course he made enemies, for he was not sufficiently measured in his treatment of opponents. Yet it might safely be said that he was not actuated by personal hostility, but only by antagonism of view. Still he was too favourable to his own work, and did not adequately appreciate other men. The general student enjoyed those peculiarities of Dr. Bennett of which he did not himself feel the brunt, but in the clinical class or in the examination hall his unsparing logical acumen tasked the student mind somewhat severely, and he was a generally dreaded examiner. From the peculiar organisation of Edinburgh work Bennett was expected to be a clinical teacher of medicine as well as a professor of physiology; thus the importance of his work in the infirmary was as great as that in the lecture-room. He was a clinical teacher of the highest order—nothing was suffered to pass unnoticed. All methods of inquiry into the patient’s case were diligently taught to the students, who were led to observe precisely and methodically for themselves. He would test and stimulate his pupils[15] most acutely by disputation, questioning, and argument; and he thus trained a body of men who carry his impress into all their work. In 1845 Dr. Bennett published a case of “Hypertrophy of the Spleen and Liver,” which is the first recorded case of a disease characterised by a great abundance of white corpuscles in the blood, now known as leucocythæmia. Although Bennett did not at first recognise its true nature, his description and subsequent labours did much to elucidate the disease, and his name must be honourably associated with the subject.