Santorio Santorio

1561-1636

Italian Physician

Santorio Santorio (Latinized as Sanctorius, or Santorius), is primarily remembered as the inventor of the clinical thermometer and the author of De Statica Medicina (On Medical Measurement, 1614). Santorio attempted to introduce quantitative experimental methods into medical research. Santorio Santorio was born in Justinopolis (now Koper). His mother was from a noble family in that region, and his father, Antonio Santorio, was a nobleman in the service of the Venetian republic. Santorio began his education in Justinopolis and continued his studies in Venice. In 1575 he entered the University of Padua and earned his M.D. degree in 1582. He served as the personal physician of a nobleman in Croatia from 1587 until 1599 when he established his medical practice in Venice, where he became a friend of Galileo (1564-1642). He was appointed to the chair of theoretical medicine at the University of Padua in 1611. As a practicing physician, Santorio appears to have relied on classical Hippocratic and Galenic methods. Instead of blindly following ancient authorities, however, Santorio urged his students to consider sense experience and reasoning, before accepting ancient authority. In 1624 his students charged him with negligence on the grounds that his private practice often took precedence over his teaching duties. Although he was found innocent, he retired from teaching and spent the rest of his life in Venice.

Santorio was a leading member of the iatrophysical school of medical thought and attempted to explain the workings of the animal body on purely mechanical grounds. In contrast to the traditional Aristotelian and Galenic qualities and essences that had been used as explanations for bodily functions, Santorio attempted to describe the fundamental properties of the body in mechanical and mathematical properties, such as number, position, and form. As an iatrophysicist, Santorio compared the body to a mechanical clock or machine. His ingenious inventions and instruments, including a wind gauge, a water current meter, a pulsilogium, and a thermoscope allowed him to describe various phenomena in numerical terms. Although there is some controversy over the invention of the thermoscope, Santorio was apparently the first to apply a numerical scale to the thermoscope and create the clinical thermometer. Galileo's experiments with pendulums probably inspired Santorio's adaptation of the pendulum to medical practice as an accurate way to determine pulse rate. The pulse clock was described by Santorio in a book that he published in 1603. Similarly, Santorio's invention of the clinical thermometer in 1612 might have been inspired by Galileo's thermoscope, a device used to measure hot and cold. The thermoscope devised by Galileo in 1597 consisted of a glass vessel about as large as an egg, with a long glass neck. When Galileo heard about Santorio's instrument, he appears to have complained and asserted his priority. Probably, Santorio deserves credit for adapting several of Galileo's inventions to medical practice and for inventing others. With his pulse clock, a clinical thermometer, and the large balance used in his metabolic experiments Santorio was a pioneer in establishing the importance of accurate physical measurements in medicine.

In order to test the ancient idea that a second kind of respiration occurs through the skin, Santorio constructed a large balance on which he often ate, worked, and slept, in order to measure fluctuations of his body weight in relation to his solid and liquid excretions. After 30 years of such measurements, he established that a large part of the food and drink that he had ingested was apparently lost from the body in the form ofperspiratio insensibilis, or "insensible perspiration." Santorio reported his observations in his landmark text On Medical Measurement (1614), which has been called the first systematic study of basal metabolism. The book was widely read and highly respected by his contemporaries.

LOIS N. MAGNER