A determination of the circulation rate in man at rest and at work : the regulation of the circulation / by Walter M. Boothby from the surgical service and respiration laboratory of the Peter Bent Brigham Hospital, Boston, Mass.

  • Boothby, Walter M.
Date:
[1915?]
Catalogue details

Licence: In copyright

Credit: A determination of the circulation rate in man at rest and at work : the regulation of the circulation / by Walter M. Boothby from the surgical service and respiration laboratory of the Peter Bent Brigham Hospital, Boston, Mass. Source: Wellcome Collection.

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    experiment after equilibrium was established and just before the circulation experiment proper. The subj ect breathed through a set of Douglas valves into a 30-litre collecting spirometer. The surfaces of the valve-discs were covered with a layer of thick machine oil; in addition, a small loop of wire was passed around the cross wires over the valve-disc and the free end rested on the disc increasing its weight slightly. These changes reduced the leakage below an appreciable point without noticeably increas¬ ing the resistance to the passage of air. The spirometer was carefully calibrated and the air volumes could be determined within 50 cc. an error of 0.2 per cent for 25 litres. The air samples were analyzed in a regular 10 cc. Haldane9 gas analysis apparatus, the error of which for routine work does not exceed 0.02 per cent. The duration of the respi¬ ration experiment was obtained by a stop-watch and determined to a fifth of a second, which would give an error of 0.05 per cent for the rest and 0.3 per cent for the work experiments. The tap was turned at the bottom of expiration both at the beginning and at the end of an experiment. The carbon dioxide elimination and the oxygen consumption per minute were cal¬ culated in the usual way, allowing for the change in volume of the expired air.10 To avoid the necessity of making a correc¬ tion for the dead space of the spirometer it was filled with ex¬ pired air and then emptied just before beginning the experiment. Temperatures.' The temperature of the gas in the collecting and recording spirometers was taken as that of the water bath at the time of measurement of the gas volume and read to 0.1°C. and the gas was assumed to be fully saturated with water vapor. The temperature of the gas in the lungs and air-passages was taken as 37°, and likewise assumed to be fully saturated with water vapor. Barometer. The atmospheric pressure was determined by a mercury barometer of the U. S. Weather Bureau type and read by means of a vernier to 0.1 mm. The observed reading was 9 Haldane: Methods of air analysis. 1912, Charles Griffin & Co., London. 10 Haldane: Methods of air analysis (p. 56). 1912, Charles Griffin & Co., London.