134 Oxygen in the Venous Blood. I 
the results, the question of the amount of oxygen in the venous 
blood in health and disease has always been considered important 
by physiologists and clinicians, although few investigations have 
been made. Not only are the observations on pathological cases 
few, but the determinations on normal individuals are even more 
scarce. The reason for this is probably that we did not have 
any means of determining blood gases in small quantities of blood 
until the Haldane-Barcroft method was devised. 
Kraus (8) determined the oxygen and CO: in the venous blood of a 
series of normal and pathological cases. Using the old blood-gas pump 
it was necessary for him to draw large quantities of blood, a circumstance 
which prevented repeated determinations in the same person. He found 
in some instances of incompensated heart cases very low values for the 
venous oxygen compared with that of normal individuals. Using the 
-Haldane-Barcroft method, Morawitz and Roéhmer (9) did eighteen deter- 
minations on three normal people, twenty determinations on nineteen 
patients with anemia, and one determination on a patient with polycy- 
themia. In some instances they found an increased consumption,’ in 
other instances a normal consumption in their patients. Means and New- 
burgh (10) using the Haldane-Barcroft method found, like Kraus, low 
values in four patients with incompensated heart diseases compared with 
those found in three normal subjects. - 
We know that in normal individuals the oxygen content of the 
venous blood is about 13.5 volume per cent, or two-thirds of 
the total amount in the blood when it is saturated. The values 
for the oxygen in the blood from an arm vein have not differed 
materially from the values obtained from the average blood flow- 
ing to the right side of the heart. A similar value has been 
obtained by calculation in the experiments on the blood flow 
done by Krogh and. Lindhard’s (11) method.’ In animals very 
varying figures have been obtained in blood from different organs 
(Bareroft, 7). 
However, our knowledge has been only approximate. Great 
variations occur; how great, or how caused, we do not -know. 
It is therefore necessary to establish the limits in not too small a 
3’The term ‘‘consumption’’ means the percentage of oxygen absorbed 
in the circulation. The arterial blood was considered saturated with 
oxygen. ¥ 
+See discussion of blood flow experiments in Paper II, J. Exp. Med., 
1918, xxvii, in press. 
