Luminaries in Medicine: Richard Mead, James Gibbs, and Solar and Lunar Effects on the Human Body in Early Modern England

In early modern England, the medical effects of the sun and the moon had been traditionally explained by a vast symbolic system of "analogies, correspondences, and relations among apparently discrete elements in man and the universe," which had its conceptual origins in the works of Aristotle, Ptolemy, and Galen. ¹ The ultimate causes of planetary emanations had been considered "occult," an Aristotelian and early modern term utilized when distinguishing "qualities which were evident to the senses from those which were hidden." ² After the Restoration, many physicians attempted to rid the natural world of occult causes and to explain invisible forces like solar and lunar emanations via mechanical, chemical, and mathematical systems.

To explain the medical effects of the luminaries, the English physicians Richard Mead (1673-1754) and James Gibbs (d. 1724) utilized iatromechanism, which regarded the body as a Cartesian machine, conforming in its functions to mechanical laws. Physiological phenomena could thus be explained in terms of physics. Archibald Pitcairne (1652-1713), professor of medicine at the University of Leyden, more specifically attempted to develop a theory of physiology called "hydraulic iatromechanism," in which the body was conceptualized as a series of canals or vessels filled with fluids. ³ Proper circulation, and the pressure and secretion of fluids in the vessels--all "mechanical, mathematizable, . . . observable entities"--were the bases of health. ⁴ Pitcairne's student Richard Mead subsequently applied Newton's gravitational theories to Pitcairne's hydraulic iatromechanism and astrological medicine. ⁵ In De imperio solis ac lunae in corpora humana et morbis inde oriundis [A treatise concerning the influence of the sun and moon on human bodies and the diseases thereby produced] (1704), Mead stressed the mechanical effects of solar and lunar emanations, especially the gravitational effects of the tides, on the pressure of vessels and fluids within the human body. ⁶ James Gibbs--taking as his theoretical basis the works of John Baptista van Helmont (1577-1644) and Franciscus de la Böe, called Sylvius (1614-1672)--combined mechanism with acid-alkali iatrochemistry to explain how lunar emanations controlled the occurrence of scrofula, the King's Evil. ⁷

Certainly, Gibbs's and Mead's use of chemical and mechanical explanations illustrates the changed intellectual climate after the Restoration, which placed rationalistic, empirical, and "scientific" values above traditional academic medicine. ⁸ While there has been little scholarly work done on Gibbs, ⁹ past writers on Mead have seen his application of Newtonianism to medicine as in character for an exemplar of these post-Restoration values. Mead's wealth, medical library, and bibliophilia, his friendships with scientists and physicians such as John Freind, Hermann Boerhaave, Hans Sloane, and Isaac Newton, and his prolific authorship made him the subject of numerous scientific biographies by his contemporaries, as well as current works by Richard Meade and Arnold Zuckerman. ¹⁰ His studies on plague and contagion have been seen as examples of rational empiricism; for instance, C.-E. A. Winslow argued that Mead was one of the first in England to postulate that plague spread via the transportation of goods from infected places, and to recommend that ships from infected ports be quarantined, and C. E. Joscelyne subsequently elucidated Mead's understanding of the "mechanical" method by which smallpox was spread, and thus how it could be countered. ¹¹ Finally, more recent studies by historians Theodore Brown and Anita Guerrini have eruditely placed Mead in intellectual context, and illustrated his contribution to the ultimately unsuccessful attempts of a group of "Newton-struck" physicians to apply Newton's work to matter theory, chemistry, and medicine from 1690 to 1713. ¹²

Mead and Gibbs may also have been prompted to portray themselves as educated adherents of the new science because of the increasing influence of...