1900s, Mask, Photograph, Spirometer Spirometer and Mask, Children’s Ventilation Measurements, 1902 March 1, 2014 Richard Johnston Leave a comment From: Untersuchungen uber die Athmunsgrosse des Kindes, by Dr. Konrad Gregor, Archiv Fur Physiologie, published by Veit and Co., 1902, page 73.