364 



THE RESPIRATION 



asphyxia and in emphysema where it is due to the curtailment of the 

 respiratory epithelium. In the latter case cyanosis is also common be- 

 cause 2 diffusion is even more interfered with (see page 407). When 

 it is compensated the blood condition shifts to area II on the chart, i.e., 

 P H is normal but the blood takes up an excess of C0 2 . This variety of 

 acidosis is more fully discussed in Chapter XLI. 



2. Addition or accumulation of nonvolatile acids, either acids absorbed 

 from the intestine or injected intravenously or when metabolic acids 

 fail to be adequately excreted such as in severe diabetic ketosis and 

 nephritis. This causes an alkali deficit. Under these conditions (area III 

 in chart) P H is low and the C0 2 absorbing power is much reduced because 



20 30 



40 50 60 70 80 



MILLIMETERS CO, TENSION 



90 



Fig. 128. Curves showing relationship between total COs in solution and PH at varying 

 CO 2 pressure. (Redrawn from D. D. Van Slyke.) 



the foreign acid has appropriated some of the base (BHC0 3 + HA = 

 BA + H 2 C0 3 ). Compensation is effected by deepened breathing (air 

 hunger) to get rid of C0 2 , excretion of acid urine and increased excretion 

 of ammonia. If compensation fails, coma is the result. If it is adequate 

 the blood condition shifts to the left on the diagram to occupy area IV, 

 i.e., P H falls within normal limits although the blood cannot take up its 

 proper amount of C0 2 . 



During muscular exercise both of the above types of acid may come 

 into play, the nonvolatile acid in this case being lactic (page 438). 



