426 



LECTURE XVIII. 



The concentration of hemoglobin in the blood amounts to 15 per cent on 

 an average. Bohr 1 computed from the above values that with a carbon 

 dioxide pressure of 30 millimeters, about 8 . 1 cubic centimeters would be 

 held in combination in 100 cubic centimeters of blood. Allowing for the 

 . 6 cubic centimeter of the gas which is held in merely physical solution 

 by the red corpuscles, then, as the total amount of carbon dioxide absorbed 

 by the corpuscles at that pressure amounts to about 14 cubic centimeters, 

 there remains unaccounted for somewhat over 5 cubic centimeters of 

 carbon dioxide. This must be combined with other substances in the 

 blood corpuscle. These other substances are evidently the alkalies present 

 which can form bicarbonates. 



We have now considered the absorption of carbon dioxide by the plasma 

 and by the corpuscles, each acting independently, and it remains to decide 

 whether such a mixture as is present in the blood has any reciprocal effect 

 upon such absorption. N. Zuntz 2 has shown that if an equilibrium has 

 been established, at a definite carbon dioxide pressure, in the exchange of 

 the dissociable substances between the plasma and blood corpuscles, that 

 a change in the pressure of the carbon dioxide will disturb this equilibrium. 

 Thus an increased pressure of the gas makes the serum more alkaline, while 

 the chlorine content simultaneously diminishes, as the following table 

 shows. It demonstrates likewise the reversibility of the entire process. 3 



INFLUENCE OF CARBON DIOXIDE UPON THE COMPOSITION OF THE 

 BLOOD IN CORPUSCLES AND SERUM. 



This increased alkalinity of the serum is explained by assuming a migra- 

 tion of the alkali carbonates to take place from the corpuscles to the 

 plasma. There is, however, no experimental evidence in support of this 

 assumption. Giirber 4 has shown that the potash is not driven from the 



1 Handbuch f. Physiol. loc. dt. p. 115. 



2 Beitrage zur Physiol. des Blutes, Inaug. Diss. Bonn, 1868. 



3 H. J. Hamburger: Osmotischer Druck und lonlehre in den mediz. Wissensch. 

 I, p. 263, Weisbaden, 1902. 



4 Sitzb. physikal. med. Ges. Wiirzburg, 1896, 28. 



Vol. 



