516 OXYGEN CONTENT OF BLOOD IN PNEUMONIC INFLUENZA. 



concluded that the apparent cyanosis observed was really a pig- 

 mentation of the skin, and was no indication of a disturbed 

 respiratory function during the earlier stages of the disease. 



In the present investigation, determinations have been made 

 of the oxygen capacity and the degree of oxygen saturation of 

 the venous blood of persons suffering from pneumonic influenza. 

 In some of the specimens the acidity and the reactivity wer3 

 determined by means of the hydrogen electrode. The presence 

 of bands due to pigments other than oxyhemoglobin was looked 

 for in the absorption spectrum of the blood, but the method 

 adopted was not found to be sensitive enough to detect the 

 jiresenee of small quantities of abnormal pigments in the pre- 

 sence of a large proportion of oxy haemoglobin . 



If the determinations of oxygen content could have been 

 made upon arterial instead of venous blood, the results would 

 doubtless have been of greater value. Venous blood passes 

 through the capillary circulation after leaving the lungs, and 

 before it reaches the veins undergoes changes, the extent of 

 which must remain largely a matter of assumption. And these 

 considerations must be of greater weight in conditions in which 

 there is an enhanced metabolism due to fever. With all these 

 reservations, however, it seems clear that, under similar patho- 

 logical conditions, pronounced variations of the oxygen content 

 of venous blood must be associated with variations in the same 

 direction of the oxygen content of the arterial blood, and some 

 recent work by Stadie (1919) has shown this to be the ease. Fur- 

 ther, there is the practical aspect of the matter; the obtaining of 

 arterial blood is an operation likely to cause considerable dis- 

 comfort to a person who is already seriously ill, while the 

 obtaining of a sample of venous blood requires only a few 

 moments, and subjects the patient to a minimum of incon- 

 venience . 



The above reservations with regard to venous blood do not 

 hold for the determinations of acidity and reactivity. The 

 methods adopted in the present investigation aimed at the de- 

 termination of decrease of available alkali or of excess of acids 

 other than carbonic acid, and as this acid is the only acid whose 

 concentration is altered by the conversion of venous into arterial 

 blood, it is a matter of indifference whether the remaining acids 

 are determined in the blood before or after arterialisation . 



The samples of blood were collected in the manner described 



