The Weighing Chair

And what, pray tell, is going on here? This macabre device is a 1694 illustration of the weighing chair of Sanctorius Sanctorius (1561-1636), an Italian scientist who was the first (that we know of) to mesh quantitative experiments with the study of how the human body works. For thirty years, Santorio measured people’s sweat.

Influenced by the Ancient Greek idea of balance in regards to health, Sanctorius thought that the optimum way to live would be to eat and drink exactly as much one would eliminate. Like, every day. So he built a special chair, connected to a scale, and measured himself (and other people, but those records didn’t survive the sands of time) day in and day out. He learned to only eat and drink exactly as much as he took in. Sort of like the world’s first Fitbit.

In his work _Ars [. . .] de statica medicina_, Sanctorius measured what he called “perspiratio insensibilis,” or the sweat that was normally undetected by the human body. He correctly surmised that a large part of the excretory process is undertaken not just by urine and excrement, but by lungs expelling air and skin emitting sweat.

Sanctorius’ chair would actually let the sitter know when she or he had taken in the exact amount of food that they would perspire/excrete out, based on earlier measurements. Sanctorius thought that health would be maintained by a balance of these factors: air and water intake, food and other drink, sleep and wakefulness, exercise and rest, sex, and affections of the mind.

The decades of measuring that Sanctorius undertook served the study of physiology well, because it used math and physics rather than qualitative statements, which obviously are important today. Sanctorius lived a healthy 75 years but no more, because no matter how much he balanced his excretions with his intake, his DNA, like all humans, had a finite time limit.