LIDDEL, DUNCAN, professor of mathematics and of medicine in the university of Helmstadt, was born in the
year 1561, at Aberdeen, where he received the elementary part of his education in languages and philosophy. About the age of eighteen he repaired to the University of Frankfurt, where he spent three years in a diligent application to the mathematics and to philosophy. From Frankfurt he proceeded to Wratislau or Breslau in Silesia, where he is said to have made uncommon progress in his favourite study of mathematics, under the direction of a very eminent professor, Paulus Wittichius. Having studied at Breslau for the space of one year, he returned to Frankfurt, and remained there for three years, giving the most intense application to the study of physic. A contagious distemper having broken out at that place, the students were dispersed, and Liddel retired to the university of Rostock. Here he renewed his studies, rather as a companion than as a pupil of the celebrated Bruceus, who, though an excellent mathematician, did not scruple to confess that he was instructed by Liddel in the more perfect knowledge of the Copernican system, and other astronomical questions. In 1590 he returned once more to Frankfurt; but having there heard of the increasing reputation of the Academia Julia, established at Helmstadt by Henry duke of Brunswick, Mr Liddel removed thither; and soon after his arrival was appointed to the first or lower professorship of mathematics. From this, however, he was promoted to the second and more dignified mathematical chair, which he occupied for nine years, with much credit to himself and to the Julian Academy. In 1596, he obtained his degree in physic, was admitted a member of the faculty, and began publicly to teach physic. By his teaching and his writings he was the chief support of the medical school at Helmstadt, was employed as first physician at the Court of Brunswick, and had much practice among the principal inhabitants of that country. Having been several times elected dean of the faculties both of philosophy and physic, he had in the year 1600 the honour of being chosen protector of the university. But neither academical honours, nor the profits of an extensive practice abroad, could make Dr Liddel forget his native country. In the year 1604 he took a final leave of the Academia Julia; and after travelling for some time through Germany and Italy, he at length settled in Scotland, where he died in the year 1613, in the fifty-second year of his age. By his last will he bestowed certain lands purchased by him near Aberdeen upon the university there, for the education and support of six poor scholars. Amongst a variety of regulations and injunctions for the management of this charity, he appointed the magistrates of Aberdeen his trustees, and solemnly denounced the curse of God against any person who should abuse or misapply it. His works are, 1. Disputationes Medicinales, Helmstadt, 1603, 4to; 2. Ars Medica succincte et perspicue explicata, Hamburg, 1607, 8vo, dedicated to James VI. and divided into five books, viz. Introductio in totam Medicinam, de Physiologia, de Pathologia, de Signorum Doctrina, de Therapeutica; 3. De Fervibus Libri tres, Hamburg, 1610, 12mo; 4. Tractatus de Dente Aureo, Hamburg, 1628, 12mo. This last production Dr Liddel published, in order to refute a ridiculous story then current, of a poor boy in Silesia, who, at seven years of age, having lost some of his teeth, produced a new tooth of pure gold. The imposture was discovered to be a thin plate of gold, skilfully drawn over the natural tooth by an artist of that country, with a view to excite the public admiration and charity. He was also the author of Artis Conservandi Sanitatem Libri duo, Aberdeen, 1651, 12mo; a posthumous work.