The effect of diet on the dissociation curve of blood 231 



exposed to 39 mm. C0 2 pressure, the following values for K are 

 obtained : 



(1) (2) (3) 



000319 -000373 -000227 



000361 -000216 -000280 



000307 -000307 '000201 



000299 -000352 -000236 



000311 -000261 -000221 



000242 -000350 



000257 -000305 



000258 

 000400 

 000283 

 000273 

 000281 



Mean -000299 -OU0309 '000233 



Of the twelve determinations given in column (1) five are above 

 the mean value, six below it, while one corresponds with it, all the 

 values in column (3) however are below the mean in column (1), and 

 all but one are below any individual figure in column (1). Since the 

 blood referred to in columns ( 1 ) and (3) was analysed at the same car- 

 bonic acid pressure there can be no doubt that the blood changed. 

 But a comparison of columns (1) and (2) shows that the values of 

 K as calculated in the two sets of figures are not really to be 

 distinguished from one another, five determinations in column (1) 

 being above the mean of column (2) and seven below it. Indeed the 

 mean value of K given in columns (1) and (2) would not yield curves 

 distinguishable from one another in diagrams of the scale and style 

 of those in this volume. 



The conclusion then is that Higgins' blood in this experiment was 

 mesectic on the fourth day, but that whilst mesectic it was abnormal 

 inasmuch as it contained less carbonic acid and an equivalent excess 

 of other acids presumably those which appeared in the urine. 



A point of some subtlety arises here let the following points be 

 accepted : 



(1) That the alveolar carbonic acid falls. 



(2) That the dissociation curve remains constant in position. 



(3) That the respiratory centre is regulated chemically by the 

 same factors as affect the dissociation curve, of which the most 

 important is probably the hydrogen ion concentration of the blood. 



The immediate deduction from considerations (2) and (3) would 

 be that the respiratory centre worked at the same rate on the days 



