Respiration experiment. Historical artwork of a physiological experiment to determine the effects of low oxygen on a bird. This experiment on respiration was carried out by the French physiologist and statesman Paul Bert (1833-1886) around 1880. The amount of air in the bell jar was gradually reduced until the bird collapsed. However once oxygen was pumped into the jar the bird recovered. This suggested to Bert that the physiological problems experienced by humans in the thin air at high altitude could be overcome if they were supplied with additional oxygen.