SOME EFFECTS OF LOW BAROMETRIC PRESSURES

In all the civilized nations of the earth, man has of late become decidedly "air-minded." The mastery of travel in the air which began with the balloon and continued with the now omnipresent airplane has helped to direct attention to those physiologic aspects of the atmosphere that are expressed in terms of barometric pressure. It is not merely a triumph of mechanical devices and human invention making possible airplane ascents to a height of nearly eight miles. This conquest of altitude includes the maintenance of physiologic functions that enable the human organism to endure the rarefied air and perform tasks without which even the most perfect flying mechanism still is doomed to possible failure or accident. The mountaineer, the balloonist and the aviator are directly concerned with modifications in human function that may be due to altitude. Barcroft and his collaborators,¹ in their account of the Andes expedition, state