# Dictionary of National Biography, 1885-1900/Duncan, Daniel

​DUNCAN, DANIEL (1649–1735), physician, of an ancient Scotch family, several members of which belonged to the medical profession, was born in 1649 at Montauban in Languedoc, where his father, Peter Duncan, was professor of physic. Having lost both his parents while he was quite an infant, he came under the guardianship of his maternal uncle, Daniel Paul, a firm protestant, like the other members of his family, by whom he was sent for his preliminary education to Puy Laurens. Here he made the acquaintance of Bayle, who was not (as is sometimes said) his pupil, but a fellow-student, two years his senior, and at that time a protestant like himself. Duncan then went to Montpellier to study medicine, and, after living for several years in the house of Charles Barbeyrac, took the degree of M.D. ​in 1673. He next went to Paris, where he became acquainted with the minister Colbert, by whom he was appointed physician-general to the army before St. Omer, commanded by the Duke of Orleans in 1677. After the peace of Nimeguen he appears to have left the army, published in Paris his first medical work in 1678, and then passed two years in London, where he employed himself especially in collecting information about the great plague of 1666. In 1681 he was summoned back to Paris to attend his patron Colbert, after whose death in 1683 he returned to his native town of Montauban. Here he was so well received that he might have remained for many years; but in consequence of the revocation of the edict of Nantes in 1685 he determined to leave the country altogether and settle in England. Accordingly in 1690 he withdrew to Switzerland, where, at first in Geneva and afterwards for some years in Berne, he employed himself, not only in the practical and professorial duties of his profession, but also especially in relieving the distress of the large numbers of French emigrants who were obliged to leave their country. In 1699 Philip, landgrave of Hesse, sent for him to Cassel, where his wife was seriously ill. Duncan was successful in his treatment of her case, and attributed her illness in a great measure to the immoderate use of hot liquors, such as tea, coffee, and chocolate, which had lately been introduced into Germany, and were indulged in to excess by the richer classes. To check this pernicious habit he wrote a little treatise in a popular style for private circulation in manuscript, which some years later he published at the suggestion of his friend Boerhaave. He resided for three years in the landgrave's palace, and while at Cassel continued his generous assistance to the numerous French protestants who emigrated into Germany. The fame of his liberality and skill reached Berlin, and procured for him a pressing invitation to that city from Frederick, the newly created king of Prussia, which he accepted in 1702. But, though he was appointed professor of physic and also physician to the royal household, he found the intemperate habits of the court so distasteful to him, and the necessary expenses of living so excessive, that in 1703 he passed on to the Hague, where he remained for about twelve years. It was not till near the end of 1714 that he was able to carry out the intention which he is supposed to have formed early in life of finally settling in England. He would have reached this country a few months earlier but that he was suddenly seized with paralysis, from which, however, with the exception of a slight convulsive motion of the head, he entirely recovered. He had often solemnly declared that if his life were prolonged to the age of seventy, he would consecrate the remainder of it to the gratuitous service of those who sought his advice. To this resolution he steadily adhered, and for the last sixteen years of his life would take no fees, although, owing to the serious loss brought upon him by the bursting of the South Sea bubble in 1721, they would have been by no means unacceptable. When one was offered to him he would say with a smile, ‘The poor are my only paymasters now, and they are the best I ever had; for their payments are placed in a government fund that can never fail, and my security is the only King who can do no wrong.’ His conversation is said to have been ‘easy, chearful, and interesting, pure from all taint of party scandal or idle raillery.’ He died in London 30 April 1735, aged 86, leaving behind him an only son, of the same name.
The following is a list of Duncan's medical works, the purport of which is sufficiently indicated by their titles, and which are no longer interesting or valuable, as being founded on the obsolete hypotheses of the iatro-chemical school of medicine. Probably Bayle correctly expressed the opinion of his contemporaries when he said that ‘the works which he had published were excellent, and did him great honour’ (Dict. Hist. et Crit., art. ‘Cerisantes,’ ii. 117, ed. 1740). 1. ‘Explication nouvelle et méchanique des actions animales, où il est traité des fonctions de l'âme,’ Paris, 1678. 2. ‘La Chymie naturelle, ou l'explication chymique et méchauique de la nourriture de l'animal,’ 1st part, Paris, 1681; 2nd and 3rd parts, ‘de l'évacuation particuliére aux femmes,’ and ‘de la formation et de la naissance de l'animal,’ Montauban, 1686. Reprinted in Latin at the Hague, 1707. 3. ‘Histoire de l'Animal, ou la connoissance du corps animé par la méchanique et par la chymie,’ Paris, 1682. Reprinted in Latin, Amsterdam, 1683. 4. ‘Avis salutaire à tout le monde contre l'abus des choses chaudes, et particulièrement du café, du chocolat, et du thé,’ Rotterdam, 1705, afterwards in English, London, 1706, and in German, Leipzig, 1707. Duncan is said to have left behind him a great number of manuscripts, mostly physical, some upon religious subjects, and one containing many curious anecdotes of the history of his own times; but where these papers are at present, or whether they are still in existence, the writer has not discovered. They are not in the British Museum.
W. A. G.