As a persevering experimentalist, Christison was daring even to rashness in making trials on himself. He thus tested the taste of arsenious acid, which was held by Orfila and most others to be rough and acrid, and which he proved to be rather sweet. He ate an ounce of the root of _Œnanthe crocata_, which had stood most poisonous in England and on the Continent; but the Scotch specimen at any rate did not poison Dr. Christison. A most striking risk was run in the case of the Calabar bean. He took a dose before going to bed, and found its effects resembled those of opium. Not satisfied, he took a larger dose next morning on rising, with the result of almost paralysing him. But he fortunately had a good emetic close at hand, a bowl of shaving water, and administering a large quantity, he was partially relieved. But much prostration remained, and medical assistance had to be summoned. Christison’s principal services to the literature of his subject consisted in his work on Poisons, which was first published in 1829, and went through several successive editions, and in numerous memoirs and papers contributed to medical and scientific journals, some of which detailed improved chemical processes and tests for poisons, as those on “The Detection of Minute Quantities of Arsenic in Mixed Fluids,” “On the Taste of Arsenic, and on its Property of Preserving the Bodies of Persons who have been Poisoned with it,” and on the poisonous properties of numerous vegetable alkaloids. In 1832 Christison, having raised his class to no fewer than ninety students, resigned his chair on appointment to that of Materia Medica, intending to become, in addition to a clinical teacher of medicine, an original investigator on the therapeutical action of remedies. But before he had got fully afloat in this, practice, for which he had not specially laid himself out, flowed in upon him, and prevented the realisation of his desire. He accumulated a fine museum of materia medica, and his lectures were very popular. But it cannot be said that he left his mark on medicine or therapeutics to the same extent that he did on toxicology. Christison was eminently a lover of his university, and exceedingly conscious of its great merits. In numerous matters he was very conservative, and strongly resisted some modern views of pneumonia and fevers. He wielded great influence for many years in the administration of university matters. In 1838 and in 1846 he was President of the Edinburgh College of Physicians. From 1868 to 1873 he was President of the Royal Society of Edinburgh. From 1857 to 1873 he occupied a seat at the General Medical Council. After having been for many years Physician-in-Ordinary to the Queen in Scotland, Dr. Christison received a baronetcy in 1871, on the recommendation of Mr. Gladstone. In the same year his bust by Brodie was presented to the university, by general subscription among the medical profession.