# Dictionary of National Biography, 1885-1900/Slare, Frederick

​SLARE or SLEAR, FREDERICK (1647?–1727), physician and chemist, grandson on the maternal side of ‘Mr. Malory of Shelton,’ Bedfordshire (Vindication of Sugars, p. 60), was born in Northamptonshire. He ascribes to ‘the great favour and manuduction’ of Robert Boyle [q. v.] whatever service he was able to render experimental philosophy, and he also came under the influence of Thomas Sydenham [q. v.] (An Account … of Pyrmont Waters, &c., p. 17). He was introduced by Robert Hooke [q. v.] to the Royal Society on 3 July 1679 to show experiments on spermatozoa, just discovered by Leeuwenhoek. He was recommended for election to the society by Theodore Haak [q. v.], one of the original fellows, was admitted fellow on 16 Dec. 1680, and became a member of the council on 30 Nov. 1682. He was admitted M.D. at Oxford on 9 Sept. 1680 (Foster); candidate of the Royal College of Physicians on 25 June 1681; fellow on 25 June 1685; censor in 1692, 1693, and 1708; elector on 21 Sept. 1708; and he was member of the council from 1716 till his death. He had a large practice in London, but being ‘troubled with a pituitous cough … due to the thick London air,’ he retired into the ‘quiet of the country,’ probably to Bath, before 1715, and died on 12 Sept. 1727 ‘in his eightieth year.’ He was buried in the cemetery adjoining Greenwich churchyard, where an inscription on his gravestone is still extant; he is described as ‘Societatis de promovendo Evangelium in partibus transmarinis socius.’ His sister Jane (d. 4 April 1734, aged 80) was buried next to him.
Slare was for some years a constant attendant at the meetings of the Royal Society, before which he showed many experiments on phosphorus, one of which, ‘a very noble experiment,’ he repeated after dinner at the house of Samuel Pepys (Evelyn, Diary, 13 Nov. 1685). His work shows independence of thought and critical power, though no great originality. He demonstrated the presence of common salt in blood (Phil. Trans. xiii. 289), and supported to some extent the views of John Mayow [q. v.] and Richard Lower (1631–1691) [q. v.] with regard to the change of colour produced on the blood by the action of air. He repeated certain experiments of Boyle with ammoniacal copper solutions in which air was absorbed, with an accompanying change of colour (ib. xvii. 898). At the request of Sir John Hoskins [q. v.], president of the Royal Society, he examined in 1713 a number of calculi, which he showed, in opposition to the view then prevalent, to be unlike tartar chemically (ib.) This research doubtless led him to write his book ‘Experiments … upon Oriental and other Bezoar-Stones’ (published in 1715), in which he disproves the miraculous virtues then attributed to these animal calculi, which were sold at as much as 4l. an ounce. He quoted cases of their inefficiency, and showed that they were unacted on by the chemical reagents at his disposal. The pamphlet was replied to at once by W. … L … in ‘A Nice Cut for the Demolisher’ (Brit. Mus. Cat.), and the superstition persisted for nearly a century longer. He suggested chalk as a remedy for acid dyspepsia instead of ‘Gascoin's powder,’ a remedy composed in part of bezoar-stones. Bound up with the foregoing pamphlet, and dedicated to ‘the ladies,’ was Slare's ‘Vindication of Sugars against the Charge of Dr. [Thomas] Willis’ (1621–1675) [q. v.], in which he characteristically rejects the experiments of Willis (De Scorbuto, cap. x.), and combats the unfounded and still existing belief that sugar injures the teeth. He falls, however, into the common error of supposing all sweet substances to be allied to sugar. In 1713 Slare had shown (Phil. Trans. xxviii. 247) that the Pyrmont mineral waters are not acid in the ordinary sense of the word, as they do not curdle milk; in 1717 he reprinted this paper, with additions, as ‘An Account … of the Pyrmont Waters,’ dedicated to Sir Isaac Newton and Dr. John Bateman (d. 1728), president of the College of Physicians, before whom he had made experiments (28 Feb. 1717), comparing the Pyrmont waters with the then more fashionable ones of Spa. He incidentally claims (p. 56) to have made and used ‘purging’ (i.e. Epsom) salts before Nehemiah Grew [q. v.] The book was translated into German in 1718 by Georg Ludewig Piderit, and annotated by Johann Philipp Seipp, with sharp and unfair criticism of Slare's views. Seipp, however, on publishing a second edition of his own work, ‘Neue Beschreibungen der ​pyrmontischen Stahl-Brunnen,’ inserted a eulogy on Slare, 1719 (p. 49).
In an appendix to Dr. Perrott Williams's ‘Remarks upon Dr. Wagstaffe's Letter against inoculating the Small-pox’ (1725), Slare defends inoculation (which had been introduced in England in 1721), and mentions having attended a son of Sir John Vanbrug[h] [q. v.], after inoculation, in May 1723. In addition to the books mentioned and the papers quoted in Maty's ‘Index to the Philosophical Transactions,’ Slare wrote two papers in Hooke's ‘Philosophical Collections’ (pp. 48, 84).
Slare's work occupies a unique position between that of the earlier physicians, who often neglected clinical observations for fantastic interpretations of chemical and physiological experiments, and the almost exclusively clinical school of Sydenham.
P. J. H.