io8 



F. G. HALL. 



equal effects are those in which they produce equal increments 

 in the hydrogen ion concentration. In Fig. 8 it will be seen that 

 the time taken for mammalian blood containing 0.2 per cent, 

 lactic acid to be reduced by nitrogen, and for blood without lactic 

 acid to be reduced by 100 per cent, carbon dioxide, are indistin- 

 guishable. But blood containing either of these solutes requires 



Nc 



niaL JHc 



ocl 



M 



1JIO 



HCL 



C 



Hla 



FIGS. 8 AND 9. Ratio of reduction of blood with a uniform stream of oxygen 

 free gas. Percentage saturation is shown vertically. Time in minutes is shown 

 horizontally. Fig. 8 shows a comparison with normal blood, with blood containing 

 lactic acid, and with blood reduced by carbonic acid instead of nitrogen. Fig. 9 

 shows the approximate equality of M/i^o HC1 and M/I2O lactic acid in their 

 effects. (From Barcroft, 1914.) 



about one tenth the time necessary for the same reduction with- 

 out acids. The blood is reduced from 100 per cent, saturation to 

 80 per cent, saturation, in about two minutes with the acids 

 present, and about twenty-two minutes with the acids absent. 



