458 



VICTOR C. MYERS 



According to these workers, as the blood passes from the arterial to the 

 venous side of the circulation in normal man its cells gain from 4 to 11 

 volumes per cent of CO 2 , while the corresponding gain in the plasma is 

 only from to 1.8 volumes per cent, indicating that the transport is ac- 

 complished mainly by the cells. Theories regarding the ability of the 

 blood to take up and hold oxygen and carbon dioxid and the equilibrium 

 between these two gases in the blood have recently been presented by L. 

 J. Henderson (c) and Y. Henderson and Haggard (&). 



Although the removal of carbon dioxid from the tissues may be ac- 

 complished mainly through the agency of the cells, still the bicarbonate 

 of the plasma is ordinarily in equilibrium with that of the cells, as Van 

 Slyke and Cullen have pointed out. Consequently the carbon dioxid capac- 

 ity of the plasma may be used as a simple practical method of measuring 

 the alkaline reserve of the body. (Whole blood may be used, and theoret- 

 ically is to be preferred, but it easily gums up the Van Slyke apparatus.) 



Acidosis may result from an abnormal formation of acid substances 

 such as is found in diabetes, or from a decreased elimination of normally 

 formed substances as in nephritis. The carbonates of the blood have 

 been called by L. J. Henderson the first line of defense against acidosis. 

 Increased pulmonary ventilation as occurs with dyspnea or hyper- 

 pnea, serves to increase the excretion of carbon dioxid, thus keep- 

 ing the reaction of the blood within normal limits. In conditions 

 of acidosis, other acids may combine with the bicarbonate, robbing the body 

 of its alkaline reserve. In diabetes this is brought about by the abnormal 

 formation of ketone bodies, while in nephritis the breakdown in the ex- 

 cretion of acid phosphate apparently brings about the same result. 



The range of the carbon dioxid combining power of the blood plasma 

 of the normal resting adult, with the Van Slyke(e) method, is from 55 to 

 75 c.c. of CO 2 per 100 c.c v with an average of 65 c.c. For normal in- 



