recognise the value of the discovery of vaccination by Edward Jenner (1749–1823) [q. v.], and were, indeed, the first to make experiments on a large scale in this matter. Soon after Jenner's first publications they vaccinated 160 patients, and subsequently inoculated sixty for smallpox, of whom none took the disease (20 Jan. to 17 March 1799). Some of these experiments seem, however, to have been vitiated by the introduction of small-pox virus into the lymph. Pearson sent out letters to doctors in England and abroad with regard to his work; and, in spite of the continental war, correspondence on vaccination was permitted between him and medical men in France and Italy (Gent. Mag.) On 2 Dec. 1799 a vaccine pock institution, which became the official institution for the army and navy, was established by his efforts at 5 Golden Square. He had not informed Jenner of his plan, though he eventually offered him the post of extra corresponding physician, an honour promptly declined. Jenner was now persuaded by his friends to come to London, and induced the Duke of York and Lord Egremont to withdraw their support from Pearson's institution. When Jenner was rewarded for his services by parliament, the claims of Pearson and Woodville were ignored, and the former at once published an ‘Examination of the Report … on the Claims of Remuneration for the Vaccine Pock Inoculation’ (1802), a violent but able and important polemic against Jenner, whom he now took every opportunity to denounce. Jenner wisely made no reply. While Pearson was evidently anxious for an undue share of credit in the matter, his claims both as a critic and a populariser of vaccination are undeniable. His objection to Jenner's term, ‘Variola Vaccinæ,’ and the identification of cowpox with smallpox which it involves, and also to Jenner's identification of cowpox with the ‘grease’ of horses, have been sustained by subsequent research (see Chauveau and others, quoted in Crookshank's History, &c. pp. 302–5). Later, Pearson seems to have lost faith in vaccination (Baron, Life of Jenner, ii. 359).
Pearson was intimate with Horne Tooke and Sir F. Burdett, but took no part in politics. He was physician to the Duke of York's household. He died from an accidental fall at his house in Hanover Square, on 9 Nov. 1828. He left two daughters.
Pearson was ‘a disinterested friend, and a good-humoured and jocose companion.’ As a practitioner he was ‘judicious rather than strikingly original’ (Munk). As a lecturer he was ‘distinct, comprehensive, argumentative, witty, and even eloquent.’ It is as a chemist, and as an early advocate of vaccination, that he will be remembered. He was one of the first Englishmen to welcome the theories of Lavoisier, and did much to spread them in England by translating in 1794 the ‘Nomenclature Chimique,’ in which he substituted, without acknowledging the source, Chaptal's name ‘nitrogen’ for ‘azote.’ As an experimenter he was methodical, ingenious, and trustworthy. His critical power is best illustrated in the memoir ‘On the Nature of Gas produced by passing an Electric Discharge through Water’ (Nicholson's ‘Journal,’ 1797, abstracted in Annales de Chimie, xxvii. 61). Among his most important chemical papers are those on the composition of carbonic acid, an extension of the work of Smithson Tennant [q. v.], which led Pearson to the discovery of calcium phosphide; on wootz, an excellent account of the properties of iron and steel; and on urinary concretions, including a chemical description of uric acid (a term invented by Pearson), which was criticised by Fourcroy in ‘Annales de Chimie,’ xxvii. 225.
[Gent. Mag. vol. xcviii. pt. ii. p. 549 (1828) and vol. xcix. pt. i. p. 129 (1829); Pantheon of the Age, 2nd edit. iii. 107; Rose's Biogr. Dict.: Munk's Coll. of Phys.; Baron's Life of Jenner, i. 312, 319, ii. 32, 359; Watt's Bibl. Brit.; Crookshank's Hist. and Pathology of Vaccination, i. 302–5, vol. ii.; Thorpe's Dict. of Applied Chemistry (Lac-Dye); Percy's Iron and Steel (1864), p. 775; Lettsom's Observations on the Cowpock, 2nd edit. 1801, gives silhouette; Creighton's Epidemics in Great Britain, ii. 563 (1894); Scudamore's Treatise … on Mineral Waters, 2nd edit. p. 12 (1833); Donaldson's Agricultural Biography; Dict. of Living Authors, 1816; Wiegleb's Geschichte der Chemie, ii. 449, 463; Gmelin's Gesch. der Chemie, passim; Kopp's Gesch. der Chemie, passim; Observations on Dr. Pearson's Examination of the Report, &c., by T. Creaser (1803), Royal Society's Catalogue.]
PEARSON, HUGH NICHOLAS (1767–1856), dean of Salisbury, only son of Hugh Pearson, was born at Lymington, Hampshire, in 1767, and matriculated from St. John's College, Oxford, on 16 July 1796. He graduated B.A. in 1800, M.A. in 1803, and D.D. as ‘grand compounder’ in 1821. He gained in 1807 the prize of 500l. offered by Claudius Buchanan [q. v.] for the best essay on missions in Asia, and printed his work in the following year at the university press under the title ‘A Dissertation on the Propagation of Christianity in Asia,’ Oxford, 4to. The interest thus aroused in Christian missionary enterprise in Asia prompted him
