522 OXYGEN CONTENT OF BLOOD IN PNEUMONIC INFLUENZA 



of postulating any alterations of the aeration of the blood itself. 

 The few figures available for the oxygen saturation of normal 

 venous blood confirm this supposition [Twort and Hill (1915), 

 Lundsgaard (1918)]. No conclusions, therefore, can be drawn 

 from a variation of the oxygen content of 30 % in either direc- 

 tion from the normal average. 



The figures in this table, therefore, give no evidence of any 

 general decrease, either in the oxygen capacity or in the oxygen 

 content of the, blood in pneumonic influenza. The averages of 

 the values given are within 5 % of the averages of normal 

 figures: oxygen capacity, 19.1% (normal 18.5%); oxygen 

 saturation, 61.2% (normal 60%); percentage of oxyhemo- 

 globin, 103 (normal 100) . 



It will be noticed that, although the majority of the values 

 obtained for the percentages of oxyhemoglobin by the colori- 

 metric method agree well with those calculated from the oxygen 

 capacity of the blood, certain of the results show differences 

 greater than the error of the method (5%). The results ob- 

 tained by the mixtures of small percentages of methaemoglobin 

 show that deviations of the magnitude observed might be due to 

 the presence of very small amounts of abnormal pigments, 

 amounts considerably lower than 5 % . Such amounts could not 

 be detected by variations of the oxygen capacity, as the normal 

 variations of this, as has been mentioned, are greater than the 

 variations under consideration. Until further information is 

 obtained however, these variations cannot be definitely attributed 

 to the presence of abnormal pigments in the blood. 



The following table shows the concentration of hydrogen ions 

 in the C0 2 free plasma of venous blood from cases of pneumonic 

 influenza, before and after the addition of twice their volume of 

 0.0196N HC1. The concentrations are expressed both as 

 equivalents of acid per litre (C ), and in Sorensen's. notation 

 in which pH = — ! The difference of pH and the cor- 



1 log C H * 



responding increase of C H , i.e. j ~ ) due to the addition of 



the acid are also shown. The figures in the columns headed 

 E.M.F. are the values in volts of the potential differences be- 

 tween the plasma and the hydrogen electrode. They are ob- 

 tained by subtracting 0.377 volts, the potential of the 0.1X 

 calomel electrode, from the observed potential. 



