The dissociation curve in man 



219 



oxygen, say 17 mm. of mercury, and ask whether the blood of every 

 individual in the absence of carbonic acid is equally saturated with 

 oxygen when exposed at 37 C. to 17 mm. oxygen pressure. Fig. 10.5 

 shows that my own blood at this pressure is 75*5 / saturated with 

 oxygen. This figure was arrived at as the result of some determina- 

 tions made by Dr Boothby of Boston, U.S.A., and myself. These data 

 will give an idea of the standard of accuracy of the methods employed. 



too 



17 MM. 



FIG. 105. Dissociation curve of Barcrof t's blood with the addition of 0, '02, '065 and 

 2 / lactic acid. The last is only an approximation. Temperature 37 C. 



Percentage saturation of blood with oxygen at 17 mm. 

 O 2 pressure and 37 C. 



Barcrof t's blood ... 78 77 73 

 Boothby's blood ... 79 77 76 

 Mean values . 



74 75 76 difference between extremes 4 / 



75 77 ,, 5/ 

 Barcrof t's blood 75 -5 % 



Boothby's blood 76-8 / 



Corresponding figures of a number of workers are : 



Boothby 76 -8% 

 Barcroft 75 -5 

 Winfield 78 

 Burn 76 

 Higgins 74-3 



Hill 74% 

 Miss Chick 73 

 Miss Pillmann 76 

 Miss Martin 79 

 Dr Klein 68 



Were it not for the single case of Dr Klein it might almost be 

 supposed that the whole of the cases given above were sufficiently 



