The Pulsilogium of Santorio: New Light on Technology and Measurement in Early Modern Medicine.

Abstract

The emergence of modern science in the sixteenth and seventeenth centuries had in medicine an important field of development thanks especially to the work of Santorio Santori (1561-1636). Mostly known for his contribution to the study of metabolism, Santorio was a pioneer in the use of quantification and developed several types of instruments, among which was a device called pulsilogium that represents the first instrument of precision in the history of medicine. First mentioned in 1602 by a colleague of Santorio in Padua, the instrument possibly constituted a source of inspiration for Galileo and sparked an entire path of experiments in seventeenth-century Europe. Santorio presented his inventions in a series of rough engravings in his Commentaria in primam Fen primi libri Canonis Avicennae (Venice 1625) promising soon to publish another book called De instrumentis medicis: a task that, unfortunately, he was never able to fulfil. As a consequence, many descriptions related to Santorio's instruments are partial or too general to provide a proper understanding of their mechanism. In order to understand the exact application of Santorio's ideas to physiology, their reconstruction represents an essential task for any historian and philosopher of science. Relying on a new assessment of Santorio's works, newly discovered documentary proofs as well as on experimentation carried out at the University of Exeter, we present here for the first time the key principles that led to the historically accurate reconstruction of the pulsilogium A2. The results are possibly of some importance in the history of science, as, unlike all previous scholars, we can now prove that the pulsilogium represented a moment of transition and departure from the late Aristotelian physics towards Galileo's mechanics and that, despite the latter's discoveries, it continued to be used not to obtain an absolute measurement of the pulse rate, but to record its 'latitude'.