The Italian physician and physiologist Sanctorius (1561-1636) is noted for his application of quantitative methods to the study of human physiology and pathology.

Sanctorius, the Latin name of Santorio Santorio, was born on March 29, 1561, at Capo d'Istria. The University of Padua, the leading medical institution of the period, provided his medical education between 1575 and 1582. After receiving his medical degree, he practiced as a physician up to 1599 in Croatia (Yugoslavia), where he had been invited by some Croatian nobility. In 1611 he assumed the chair of theoretical medicine at Padua and held this distinguished post until 1624, when he went to Venice. He died in Venice on Feb. 22, 1636. He endowed an annual lectureship at Padua, which is still continued.

As is typical of many pioneers, Sanctorius, without realizing the full value of his ideas, recognized the necessity of measurement in medicine. Therefore he directed all his energies toward one goal: the development of instruments and appliances which would permit the physician investigator to quantify all known facts about the body.

Sanctorius's classic experiment was carried out over a period of 30 years, during which he spent as much time as possible seated in a chair rigged up to a balance so that he could weigh himself frequently. He also weighed all the food he ingested and all the excreta that he passed. These measurements provided convincing evidence for the existence of the then controversial "insensible perspiration," by which volatile substances were supposed to leave the body. He published his results in De medicina statica aphorismi (1614), of which there were 32 editions up to 1784 and many translations into modern languages. Sanctorius's constant endeavors to conduct systematic measurements entitle him to rank among the founders of experimental medicine.

Sanctorius gave impetus to the iatrophysical school of medicine, that is, the school which explained all body processes and diseases and their treatments within a numerical and geometrical context. However, iatrophysics began to flourish outside of Italy only in the early 18th century, three-quarters of a century after Sanctorius's death.

Among the instruments Sanctorius invented or perfected for use in physiology and pathology are the balance, the thermometer, the hygrometer, the trocar (for removing excess water from the abdomen and the chest), and a catheter for removing kidney stones. The best-known of these instruments is the thermometer described by Sanctorius in his commentary on Arab medicine. He also developed an apparatus for measuring pulse rates by comparing them to the swings of a pendulum on strings of different lengths. Then, by comparing the string lengths, the pulse rates were calibrated as a function of time. Thus, medieval medicine and Renaissance physics were combined in the imaginative mind of Sanctorius to develop this important instrument.

Further Reading

• There are no books on Sanctorius in English. Most biographical accounts are in Italian. The closest to a definitive biography is in Serbian by Mirko Drazen, Santorio Santorio (Zagreb, 1952); it includes a few pages of summary in English. For background see Henry E. Sigerist, The Great Doctors: A Biographical History of Medicine (trans. 1933); Ralph H. Major, A History of Medicine, vol. 1 (1954); and Katherine B. Shippen, Men of Medicine (1957).