230 



Chapter XV 



mind of the reader is Were the experimental methods at our com- 

 mand equal to the task of discerning any shifting of the curve, should 

 it exist? The answer to this question is given in the figure. The dark 

 spots (Fig. 110 A) are those obtained by exposing Higgins' blood, 

 taken during the diet, to the alveolar pressure of carbonic acid which 

 existed before the diet 37 38 mm. of mercury. It is clear that all 

 these points are below the curve. 



The absence of any carbohydrate metabolism is shown by the 

 figures which were obtained for the respiratory quotient. 



Higgins' dissociation curve had been very carefully determined 

 before the experiment began. In each case blood was exposed to 

 the carbonic acid pressure of the alveolar air at the time the blood 

 was taken. 



The comparison may be put before the reader in another way. 



It has been pointed out in Chapter IV that all human dissociation 

 curves fit the general equation 



Kx n 



100 ~ 1 + Kx n ' 



in which n may be taken as 2'5. The only variable then is K. If 

 the values of K be calculated for the observed points (1) of the 

 normal blood exposed to normal alveolar C0 2 pressure of 39 mm., 



(2) blood drawn on the fourth day of the carbohydrate-free diet 

 exposed to the alveolar C0 2 pressure of the person at that time, 



(3) the blood drawn on the fourth day of the carbohydrate-free diet 



