RESPIRATION 107 



as it flows from a vessel, the corpuscles are capable of taking up 

 from pure CO 2 > more combined CO 2 than an equal volume _pf 

 the plasma. If, on the other hand, the blood is artificially saturated 

 with pure CO 2 , or air containing a high percentage of CO 2 , and 

 then separated into plasma and corpuscles, the plasma contains 

 more combined CO 2 than the corpuscles. He concluded that alkali 

 previously combined with haemoglobin in the corpuscles combines 

 with CO 2 when a high concentration of the latter is present, and 

 passes out as bicarbonate into the plasma. Further investigation 

 of this phenomenon by Giirber 7 showed that alkali does not pass 

 out of the corpuscles, but acid passes in, leaving the corresponding 

 alkali behind in the plasma. The walls of the corpuscles seem, 

 therefore, as Hamburger 8 in particular has pointed out, to be 

 practically impermeable to sodium and potassium ions, but per- 

 meable to chlorine and other anions. Hence the proportions of 

 alkali to chlorine, etc., in the plasma depend upon the corpuscles, 

 and are regulated by them according as the pressure of CO 2 in 

 the blood rises or falls. Yandell Henderson and Haggard, who 

 have quite recently investigated this phenomenon closely from 

 the physiological standpoint, point out what striking effects this 

 regulating action may produce. 9 During forced breathing, for 

 instance, the weakly combined alkali of the plasma may be con- 

 siderably diminished, although the total weakly combined alkali 

 in the blood need not necessarily be altered. 



The relation of the corpuscles to the available alkali in the 

 plasma suggests at once the question whether there is not a similar 

 relation as regards other tissue elements. Henderson and Haggard 

 showed that with vigorous and continued artificial respiration 

 the available alkali in the whole blood, and not merely in the 

 plasma, diminishes greatly, and that this diminution is accompa- 

 nied by signs of irretrievable damage to the body. This suggests 

 excessive draining of acid from the tissue elements with the 

 result that the whole body suffers, although the alkalinity of the 

 blood itself is partly prevented from falling. The matter will, 

 however, be discussed further in Chapter VIII. 



7 Giirber, Sitz-der. d. physik-med. Gesellsch. zu Wurzburg, p. 28, 1895. 



Anionenwanderungen in serum und Blut unter den einfluss von CO 2, saure und 

 alkali. Biochem. Zett. Vol. 86, p. 309-324, 1918. 



9 Haggard and Henderson, Journ. of Biol. Chem., XLV, p. 199, 1920. 



