. Barometric pressure : researches in experimental physiology. Atmospheric pressure; Physiology, Comparative; Anoxemia; Altitude, Influence of. 692 Experiments asphyxia at a degree of oxygen lack and in expanded air at a de- gree of decompression in which the oxygen tension is identical. So, in dogs, respiratory disturbances appear in confined air at about the time when there is only 12 per cent of oxygen; in pure air, they appear at about the pressure of 43 cm., a pressure which is met at about 5000 meters altitude; in both cases the oxygen ten- sion is the same, for 12 x 76 = x As
. Barometric pressure : researches in experimental physiology. Atmospheric pressure; Physiology, Comparative; Anoxemia; Altitude, Influence of. 692 Experiments asphyxia at a degree of oxygen lack and in expanded air at a de- gree of decompression in which the oxygen tension is identical. So, in dogs, respiratory disturbances appear in confined air at about the time when there is only 12 per cent of oxygen; in pure air, they appear at about the pressure of 43 cm., a pressure which is met at about 5000 meters altitude; in both cases the oxygen ten- sion is the same, for 12 x 76 = x As to serious symptoms, nausea, etc., the proportion of oxygen in the confined air must drop to about 8 per cent, or the barometric pressure of the pure air must be reduced to about 30 cm., which corresponds to a height of 7300 meters; the oxygen tension is the same in both Fig. 54—Maxima and minima of cardiac pressure in asphyxia without carbonic acid. Now—new confirmation—, it is at these altitudes approximately that the symptoms and disturbances which constitute "balloon sickness" occur in aeronauts, motionless in their basket. The agreement becomes still more interesting when it concerns observations on man himself. The most important are contributed by M. Felix Leblanc,2 who had the opportunity to analyze the air of the mines of Poul- laouen and Huelgoat, in Brittany, whose treatise contains valuable information about the sensations of the miners. The pyrites which are present in abundance in the veins being worked combine with a part of the oxygen in the air, which is thus lessened without being tainted at the same time by carbonic acid or other gases, as happens in confined places. From the data reported by M. Leblanc we extract the following: A: In a place where there is only per cent of oxygen, respiration is only slightly affected, but the air is considered "weak" by the miners;. Please note that these images are extracted from sca
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