PROJECT NO: X-409(Av-221-f) REPORT NO: One TITLE- THE RELATIONISHIPS IN VIVO BETWEEN CARBON MONOXIDE, OXYGEN AND HEMOGLOBIN 1i? THE BLOOD OF MAN AT ALTITUDE.

1 Three male subjects have been studied at varying pressure-altitudes while in eouilibrium with inspired gas mixtures containing from 0.005 to 0.015 per cent car-bon monoxide. 2. The distribution of COHb, 02Hb and reduced Hb and their related gas tensions confirm in vivo the fundamental "laws " first defined by Haldane for the eouilibria obtain-ing in vitro. 3. A simple rearrangement of the Haldane equetion makes possible an accurate prediction of the amount of COHb obtaining when man is in eauilibrium with a CO-contaminated atnosphere at any riven altitude. The euation, (COHb)0 x (Total hemorlobin saturation