Sir John Floyer (1649–1734) was an English physician and alchemist renowned for his diverse contributions to early modern medicine. His interests and writings bridged the fields of medicine and alchemy, showcasing an innovative blend of empirical science and philosophical exploration.

Pulse Measurement: Floyer pioneered the practice of measuring the pulse rate using a specially designed watch, advancing diagnostic accuracy and establishing a precedent for time-based physiological assessments.

Cold Bathing Advocacy: As an advocate of cold bathing for therapeutic benefits, Floyer authored works extolling its restorative effects, a stance that contributed to the development of hydrotherapy.

Asthma Research: Floyer’s observations on asthma and lung pathology provided some of the earliest documented insights into conditions like emphysema.

In Pharmako-Basanos: or the Touchstone of Medicines, Floyer applies an alchemical perspective to understanding the properties of medicinal substances, focusing on their virtues as revealed through taste and smell. This work exemplifies his commitment to integrating alchemical principles with early scientific methodology, exploring medicine not only as a science but as an art with philosophical and esoteric dimensions.