Santorio Santori (also SantorioSanctorius or De’ Sanctoriis) was a Venetian physician, philosopher and inventor who introduced the quantitative method to medicine and biology. He is universally recognized as the father of modern experimental physiology.



The first son of Antonio Santorio and Elisabetta Cordoni (or Cordonia), Santorio was born in Capodistria, today Koper in Slovenia, on 29 March 1561. He studied philosophy, mathematics and music in Venice with Andrea Morosini (1558-1618), graduating in medicine at the University of Padua in 1585. Around this period, he began his experiments on the homeostatic balance of the body (perspiratio insensibilis) and befriended the Servite friar Paolo Sarpi (1558-1621) and the future Doge Niccolò Contarini (1553-1631). Following a period of journeys in Hungary, Poland, and Croatia (approx. 1589-1593), Santorio settled in Venice, where he also partook in the early gatherings of the so-called Ridotto Morosini, an intellectual circle of politicians, philosophers and historians linked by a strong opposition to the Papal and Spanish politics, also attended by Galileo Galilei (1564-1642). The relation between Galileo and Santorio has always remained a puzzle to historians, with recent studies and discoveries confirming the independence and originality of Santorio’s quantitative research. Santorio’s reputation as a physician, especially after the publication of his first work on method (Methodi Vitandorum Errorum Omnium qui in Arte Medica Contingunt Libri XV, Venice 1603) and the political connections he had established within the Venetian intelligentsia led to his appointment to the first chair of medicine at the University of Padua (1611-1624), followed a few years later by that at the Collegio Veneto (1616-1618, 1622-1624), an institution created to grant non-Catholic students a degree in medicine without the need to make public profession of Catholic faith. In his capacity as the president of that institution, as well as a representative of the anti-papal strategies plotted by Contarini and Sarpi, Santorio faced opposition and criticism by the Papal nuncius Berlingiero Gessi (1563-1639). Due to these conflicts, which were soon followed by the death of Sarpi (1623), Santorio became politically isolated and quickly fell out of favor with the new conservative establishment. Upon the Senate failing to renew his increase of salary, Santorio resigned from his position (1624) and was replaced by the less talented, but openly pro-papal physician Pompeo Caimo (1568-1631). During the outbreak of plague 1630-31 he remained in Venice where he eventually died a few years later, on 25 February 1636.


Santorio’s place in the history of science and medicine rests primarily on his contribution to the development of the experimental method. Most notably, his merits lie in the elaboration of an early form of corpuscularianism, and above all in the invention of precision instruments meant to ascertain the homeostatic balance of the body, especially with regards to pulse frequency, temperature, and insensible perspiration. These factors were indeed measured with special instruments called pulsilogia, with thermometers (hydrolabia Sanctorii) and by means of a weighing chair, also called sella Sanctorii.

Santorio’s Weighing Chair (Sella Sanctorii)

Matter is conceived by Santorio as a granular texture, whereby small bodies (corpuscula minima) are put in motion by a vortex (motus aliquod velocissimus). The fundamental qualities of matter are therefore geometrical, namely shape, number, position and the bodily functions are akin to those of a clockwork, an analogy later adopted by Descartes. Santorio’s interest in the quantitative aspects of medicine led him to regard all morbid conditions in terms of a linear distance from a physiological state (recessus a statu naturali), which allowed him to establish a direct connection between the severity of a disease and its evaluation in quantitative terms. This early insight, reworked from the Galenic diagnostic rationale, was later expanded in his commentaries on Galen’s Art of Medicine and Avicenna’s Canon (Santorio 1612, 1625) and above all in the Ars de statica medicina (Venice 1614), Santorio’s masterwork, which saw more than 54 reprints in less than 150 years, becoming a fundamental textbook in European medical practice. By means of his works Santorio established the principle that physical transformations are necessarily associated with quantitative parameters, and that physicians’ subjective appreciation of the individual conditions of their patients is deceptive if not mediated by the use of precision instruments. For these reasons, Santorio has often been considered one of the founding fathers of iatromechanism and his contributions to medicine have been considered of comparable standing to those of William Harvey while his experiments influenced generations of physicians and philosophers, being eventually superseded by those of Lavoisier and Séguin.


Fabrizio Bigotti