ACIDOSIS 



61 



son (1909) estimates that carbonic and phosphoric most nearly approxi- 

 mate maximum efficiency at the blood reaction, despite the fact that the 

 blood pll is not very near the point of maximum efficiency of either buffer. 

 It is of importance, however, that this point is in both buffers at a lower 

 pH than that normal for blood, so that if the blood pH falls, the phosphate 

 and carbonate buffers oppose the change with an efficiency which increases 

 as the change approaches the danger point. At pH 6.95, which appears 

 to be the most acid point consistent with life an man, the phosphates have 

 very nearly their maximum buffer efficiency. 



While the organism has appropriated the best available, although 

 not ideal, buffers that the external laboratories of nature offer, it appears 

 to have manufactured, in the chief blood proteins, buffers of its own 

 which are nearly ideal. 



b. The Interchange of Buffer Effects Between Blood Cells and Plasma. 

 It remains to add an account of the peculiar manner in which buffer 

 effects are interchanged between cells and plasma. The cells are much 

 richer in the buffers effective at blood pH than is the plasma, but by 

 means of interchanging HC1 and H 2 CO 3 are able to extend their buffer 

 effect to the plasma, even though the buffers themselves (hemoglobin and 

 phosphate) do not leave the cells. 



Below is a diagram which although from lack of available data it is 

 necessarily incomplete, nevertheless appears to represent the chief buffer 

 factors that maintain the constancy of the blood pll, and to indicate the 

 anion exchange that makes the cell buffers available to the plasma. The 

 equilibria as written are all shifted from left to right by increase in 

 H 2 CO 3 . 



"Na Protein" is used to indicate the total alkali salts of the plasma 

 proteins, "H Protein" the free proteins not combined with base. Sim- 

 ilarly "KHbO" and "HHbO" are used to indicate the alkali salt of oxy- 

 hemoglobin and the oxyhemoglobin not combined with alkali, respectively. 

 "KHb" and "HHb" are used similarly for reduced hemoglobin. In the 

 plasma 4he base is indicated as Na, in the cells as K, to indicate the fact 



