Frontispiece engraving showing Santorio Santorio sitting in the balance that he constructed to determine the net weight change over time after the intake and excretion of food stuffs and fluids. Santorio Santorio (1561-1636) was an Italian physiologist, physician, and professor. He introduced the quantitative approach into medicine. His work De medicina statica influenced generations of physicians. For a period of thirty years Santorio weighed himself, 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. This important experiment is the origin of the significance of weight measurement in medicine. He is still celebrated as the father of experimental physiology. The "weighing chair" (pictured here) which he constructed and employed during this experiment is also famous. Santorio also designed the clinical thermometer and invented an early waterbed.