ABSTRACT
Physician Max von Pettenkofer (1818–1901) designed a sprawling mechanism in 1862, which he named a “respiratory apparatus.” Despite the implication of its name, this unique device was not a medical ventilator. It was composed of mainly two parts: a sheet iron chamber in the form of a cube with sides eight feet (2.40m) in length and a complex piping mechanism attached to the chamber (Figure 3.1). The chamber was austere, with a door and a window outside and a single bed, table, and chair inside. According to Pettenkofer, it provided the smallest space to comfortably house a human subject for a 24-hour period. By analyzing the contents of the air entering and exiting the chamber, Pettenkofer measured the exact amount of carbon dioxide and water vapor discharged by the subject while engaged in daily activities. 1 His ultimate goal was to calculate the optimal air exchange required in a room for a person to remain healthy and comfortable.
