The experimental methods of the New York State Commission on Ventilation

Since December 8, 1913, the New York State Commission on Ventilation has been conducting an extended series of experiments on the physiological and psychological action of various atmospheric conditions. For most of the tests human beings have served as subjects; a few lines of observation have been carried out on animals. The rate of the heart beat and the blood pressure have been studied by the usual methods and have subsequently been evaluated according to the Crampton, the Barach and other indices. Bodily temperature has been measured chiefly by clinical thermometers and at times by the constant temperature recorder of Leeds and Northrup. This instrument consists of a self-balancing Wheatstone bridge, is sensitive to one tenth of a degree, and makes on paper a continuous record of rectal temperature. The apparatus proved very prone to get out of order and for this reason could not be used as constantly as was desired. Muscular work was performed by the lifting of dumb-bells to a given height, the number of lifts being recorded by a telephone counter. For more exact determinations of the amount of work performed a Krogh bicycle ergometer was employed and proved very satisfactory.

Respiration was studied by determining its rate and the volume of air respired, the carbon dioxide tension of the alveolar air by the Haldane method, and the volume of the dead space by the method of Douglas and Haldane, while the acidity of the blood was tested by means of both the carbon dioxide tension of the alveolar air and the dissociation curve of the hemoglobin by the method of Barcroft. By the usual methods determinations were made of the respiratory quotient, the amounts of carbohydrate and protein metabolism, the production of heat, and the specific gravity and freezing-point of the urine.