Santorio Santorio
Born	29 March 1561 Capodistria, Republic of Venice
Died	25 February 1636(1636-02-25) (aged 74) Venice, Republic of Venice
Alma mater	University of Padua
Known for	Discoveries concerning metabolism and invention of technical instruments

Santorio Santorio (29 March, 1561 – 25 February, 1636^[1]) also called Santorio Santori,^[2] Santorio de' Sanctoriis, or Sanctorius of Padua^[3] and various combinations of these names, was an Italian physiologist, physician, and professor, who introduced the quantitative approach into the life sciences and is considered the father of modern quantitative experimentation in medicine. He is also known as the inventor of several medical devices. His work De Statica Medicina, written in 1614, saw many publications and influenced generations of physicians.^[4][5]

Life

Santorio was born on 29 March, 1561, in Capodistria, in the Venetian part of Istria (today in Slovenia).^[6] Santorio's mother, Elisabetta Cordonia, was a noblewoman from an Istrian family. Santorio's father, Antonio, was a nobleman from Friuli working for the Venetian Republic as chief of ordinance of the city.^[7]

He was educated in his home town and continued his studies in Venice before he entered the University of Padua in 1575,^[8] where he obtained his medical degree in 1582. He became a personal physician to a Croatian nobleman from 1587 to 1599, and he set up a medical practice in Venice, where he met Galileo.^[9]

Santorio died in Venice on 25 February 1636^[10] caused by complications of a urinary tract disease that he suffered from for many years, and he was buried in Servants of the Blessed Virgin Mary Church (Italian: Santa Maria dei Servi).^[11]

Work

From 1611 to 1624, Santorio was the chair of theoretical medicine at the University of Padua where he performed experiments in temperature, respiration and weight. He resigned from the university in 1624, due to political opposition from the senate. His Professor title and pension were kept for one year after he retired, as he returned to practice medicine in Venice in 1625. In 1630, he was one of the members of the Venetian College of Physicians appointed to cure the Venetian plague.^[12]

His practices and thinking followed Hippocratic and Galenic principles, but his keen experimentalism marks him as a representative of the 17th Century iatrophysical school of medicine.^[13] This school of thought focused on application of mathematics and physics to the study of physiology.^[14]

Inventions

Santorio was the first to use a wind gauge, a water current meter, the pulsilogium (a device used to measure the pulse rate), and a thermoscope.^[14] His pulsilogium and thermometer predates similar inventions by Galileo Galilei, Paolo Sarpi and Giovanni Francesco Sagredo who were his learned circle of friends in Venice.^[15] Santorio introduced the pulsilogium in 1602 and thermoscope in 1611.^[16]

The pulsilogium was probably the first machine of precision in medical history. Extensive experimentation with his new tool allowed Santorio to standardise the Galenic rationale of the pulse and to describe quantitatively various regular and irregular frequences.^[17] A century later, another physician, François Boissier de Sauvages de Lacroix used the pulsilogium to test cardiac function.^[13]

Study of metabolism

Sanctorius studied the so-called perspiratio insensibilis or insensible perspiration of the body, already known to Galen and other ancient physicians, and originated the study of metabolism.^[11] For a period of thirty years, Santorio used a chair-device to weigh himself and everything he ate and drank, as well as his urine and feces. He compared the weight of what he had eaten to that of his waste products, the latter being considerably smaller because for every eight pounds of food he ate, he excreted only 3 pounds of waste.^[18] Santorio also applied his weighing device to study his patients, but records of these experiments have been lost.^[11]

His notable conclusion on finding this was that:

Insensible Perspiration is either made by the Pores of the Body, which is all over perspirable, and cover’d with a Skin like a Net; or it is performed by Respiration through the Mouth, which usually, in the Space of one Day, amounts to about the Quantity of half a Pound, as may plainly be made appear by breathing upon a Glass.^[14]

This important experiment is the origin of the significance of weight measurement in medicine.^[19] While his experiments were replicated and augmented by his followers and were finally surpassed by Antoine Lavoisier in 1790, he is still celebrated as the father of experimental physiology. The "weighing chair", which he constructed and employed during this experiment is also famous.^[13][18]