(b. Sambter, Poland, 3 September 1603; d. Liegnitz, Poland, 8 June 1675)
natural history, medicine.
Of Scottish extraction, Jonston gained an extensive education while traveling (sometimes as a private tutor) in Germany, Scotland, England, and Holland. He attended St. Andrews, Cambridge, Leiden, and Frankfurt universities, Obtaining M.D. degrees in 1632 at Cambridge (ad eundem) and Leiden, where he later practiced medicine. He refused the chair in medicine at Leiden in 1640, but in 1642 he did become, for a short while, professor of medicine at Frankfurt.
Jonston’s widespread education is reflected in his prolific and wide-ranging writings, which comprise natural history, medicine, and miscellaneous works. Commentators on his books have tended to dismiss them as mere compilations, exhibiting more learning than judgment. There is some justice in this view, especially with regard to his extensive publications on natural history, in which he often relied heavily on the writings of others, for example, Aldrovandi. But that Jonston’s works failed to reach the standard of critical organization set by some of his contemporaries should not overshadeow the significant contribution his works made to the growing interest in natural history during the first half of the seventeenth century. For example, four of his dictionary-style works on fish, birds, quadrupeds, and insects—published between 1650 and 1653 with excellent illustrations—were widely read and translated.
Of Jonston’s many medical writings, his best known is Idea Universae Medicinae Practicae (Amsterdam, 1644), which was published in five editions. The book also appeared with commentaries by J. Michaelis and T. Bonnet, and was translated into English by Nicholas Culpeper (1652). Jonston’s book emphasized the teaching of clinical medicine to students, and therefore represented an interesting choice for Culpeper, about half of whose work was undertaken in response to the needs of the English apothecaries, then increasingly numerous and influential.
Since Jonston made it clear that his text owed much to Daniel Sennert, it is no surprise that the work is both systematic and Galenic in outlook. Despite this debt to Sennert, Jonston’s own conciseness and care in preparing the text made it eminently suitable for students. A wide-ranging wirk, it dealt not only with clinical conditions, but also provided summaries on, for instance, materia medica and on the importance of non-naturals (which he listed as air, meat, drink, motion and rest, sleep and watching) in the preservation of health. Jonston’s emphasis on signs and symptoms undoubtedly contributed to a growing empirical outlook in clinical medicine, an influence enhanced by Michaelis’ commentary on Jonston, which has already been mentioned.
Jonston’s miscellaneous works include items of general scientific interest, such as his De Naturae Constantiae (Amsterdam, 1652; English translation, 1657). Through many examples Jonston indicated that both natural phenomena and human nature had not changed since classical times. His theme perhaps reflected conservatism in his own views; but concerning the theory of matter, he considered that there were three elements (rather than four); he believed that fire was the supreme part of pure air and asked, “since the Scripture doth no where speak of fire . . . why should we maintain it?” He accepted Paracelsian views that salt, sulfur, and mercury were the fundamental constituents of matter, and favored this tria prima theory because of the prominence of the number three —as in, for instance, the Trinity, the three spirits of man (animal, vital, and natural), and the three types of vessels (nerves, arteries, and veins). He also spoke of three humors in the blood, although it is not clear whether he dismissed the traditional four-humor theory, which he held in his Idea Universae Medicinae Practicae. Jonston’s writings were a useful contribution to seventeenth-century thought, although he was not in the forefront of changing concepts of the time.
Lists of Jonston’s writings may be found in J. P. Niceron, Mémoires pour servir a l’histoire des hommes illustres, 41 (1740), 269-276; and the Dictionary of National Biography.
Other valuable sources are T. Bilikiewicz, “Johann Jonston (1603-1675) und seine Tätigkeit als Artz,” in Sudhoffs Archiv, 23 (1930), 35-381; and T. Bilikiewicz, Jan Jonston (Warsaw, 1931).
J. K. Crellin