DIMSDALE, Thomas, Baron, greatly distinguished by his practice of inoculation for the small-pox, was the son of a surgeon and apothecary at Theydon-Gernon, in Essex, and was born in the year 1712. His family belonged to the society of Quakers; and his grandfather accompanied William Penn to America, but soon afterwards returned and settled in his native village. Thomas was brought up to his profession, first under his father, and afterwards in St Thomas Hospital, London. He commenced his practice at Hertford about 1734, and married the only daughter of Nathaniel Brassey, of Roxford, near that town, an eminent banker in London, and representative of Hertford in four successive parliaments. But this lady died in 1744, leaving no children. To relieve his mind under the loss of his wife, he voluntarily offered his assistance to the physicians and surgeons in the army under the Duke of Cumberland, and continued with it until after the surrender of Carlisle to the king’s forces, when he received the duke’s thanks, and returned to Hertford. In 1746 lie married Anne Iles, a relation of his first wife, and by her fortune, and that which he had acquired by the death of the widow of Sir John Dimsdale of Hertford, he retired from practice; but his family becoming numerous, and seven of his ten children being living, he resumed it, and took the degree of doctor of medicine in 1761. Having fully satisfied himself concerning the new method of treating persons under inoculation for the small-pox, he published his treatise on this subject in 1776, and it was soon circulated all over the Continent, and translated into all the modem languages, not excepting the Russian. He [7:8:32] concludes with saying that, “although the whole process may have some share in the success, it, in my opinion, consists chiefly in the method of inoculating with recent fluid matter, and the management of the patients at the time of eruption.” This proof of his professional knowledge occasioned his being invited to inoculate the Empress Catherine and her son in 1768, of which he gives a particular account in his Tracts on Innoculation, 1781. His reward for this was an appointment of actual counsellor of state and physician to her imperial majesty, with an annuity of L.500; the rank of a baron of the Russian empire, to be borne by his eldest lawful descendant in succession, and a black wing of the Russian eagle in a gold shield in the middle of his arms, with the customary helmet, adorned with the baron’s coronet, over the shield: he also received immediately L.10,000, and L.2000 for travelling charges, besides miniature pictures of the empress and her son, and the same title to his son, to whom the grand duke gave a gold snuff-box, richly set with diamonds. The baron inoculated numbers of people at Moscow; and, resisting the empress’s invitation to reside as her physician in Russia, he and his son were admitted to a private audience of Frederick II. king of Prussia, at Sans Souci, and thence returned to England. In 1779 he lost his second wife, who left him seven children. But he afterwards married Elizabeth, daughter of William Dimsdale of Bishops-Stortford, who survived him. He was elected representative of the borough of Hertford in 1780; and declined all practice, except for the relief of the poor. He went to Russia once more in 1781, in order to inoculate the late emperor and his brother Constantine, sons of the grand duke; and as he passed through Brussels, the Emperor Joseph received him in private, and wrote in his presence a letter, which he was to convey to the Empress of Russia. In 1790, his son, Baron Nathaniel, was elected member for the borough of Hertford, on his resignation and retirement to Bath for several winters; but at last he fixed altogether at Hertford, and died, at the age of eighty-nine, on the 30th December 1800, after an illness of about three weeks. About seventeen years before his death he felt the sight of one eye declining, having before lost that of the other, but recovered both by the operation of the cataract, by Wenzel.