Among the mechanisms operating in the anemic person to compensate for the decreased oxygen-carrying power of the blood are certain alterations in the physical and chemical properties of the peripheral blood which merit consideration. We have already considered1 the alterations in pulse, respiratory rate and arterial blood pressure which ensue when such persons are subjected to exercise; we have regarded them as a rough test of cardiac competency. Here we wish to consider the problem briefly from the standpoint of the tissues to which oxygen must be supplied. According to accepted views, the supply may be maintained adequately by (1) an increase in the volume of blood supplied to any given area during a unit of time and (2) more complete extraction of oxygen from this blood by the tissues.
Our study should properly have included changes in the minute volume output of the heart, but since such determinations