Described in text as a 30 liter recording spirometer. From: Boothby WM. The determination of the circulation rate in man at rest and in work. Amer J Physiol, 1915, v37, p383.
From: Benedict FG, Miles WR, Roth P, Smith HM. Human vitality and efficiency under prolonged restricted diet. Published 1919 by the Carnegie Institute of Washington.
The diverse, quirky and mostly forgotten history of Pulmonary Function testing