From 1611 to 1624, Santorio was the chair of theoretical medicine at the
University of Padua where he performed the very first experiments on bodily
temperature,
insensible perspiration 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. Santorio's place in the history of science and medicine rests primarily on his contribution to the development of experimental methods. 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 regard to pulse frequency, temperature, and insensible perspiration. These factors were in fact measured with special instruments called
pulsilogia, with thermometers (
hydrolabiaSanctorii), and by means of a weighing chair, also called
sella Sanctorii, to which Santorio's name is still associated nowadays. His
pulsilogium and thermoscope predate similar inventions by
Galileo Galilei,
Paolo Sarpi and
Giovanni Francesco Sagredo who were his learned circle of friends in Venice. 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 frequencies. A century later, another physician,
François Boissier de Sauvages de Lacroix used the pulsilogium to test cardiac function.
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. 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
faeces. 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. Santorio also applied his weighing device to study his patients, but records of these experiments have been lost. 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. == Bibliography ==