C. Lundsgaard 135 
number of normal individuals before we can hope to be able to 
interpret results from abnormal individuals. This paper is a re- 
port of thirty-eight determinations on twenty normal individuals. 
Technique. 
Two operations are involved: first, the drawing of a sample of 
venous blood; and second, the determination of its oxygen content. 
The determination of the oxygen has been done by Van Slyke’s 
method (12): This method is quicker, easier to handle, and more 
exact than the Haldane-Barcroft, where the great volume of 
foreign air in the apparatus requires elaborate facilities for keep- 
ing the temperature constant. A determination with Van 
Slyke’s apparatus (including cleaning of the machine) requires 
5 to 10 minutes. The figure can be read with an accuracy of 
0.004 cc. Adding to this the inevitable error in measuring and 
delivering 2 ec. with a pipette, we can say that the difference 
between duplicates can always be-kept within 0.01 cc. of oxygen, 
which is 0.5 volume per cent of the 2 cc. of blood analyzed. As 
will be seen from the tables, duplicates usually agree much more 
closely. Greater differences are caused only by gross errors, 
such as by imperfect mixture of the corpuscles in the blood, or 
by allowing time for a slow oxidation (or deoxidation) of the 
blood between the two determinations (see below). 
The other part of the technique, the obtaining of 4 sample of 
blood, has been as follows: The arm from which the blood is 
drawn rests comfortably at the side of the body on a small, 
moderately soft pillow. The blood is drawn without stasis 
and the pulse and respiration are counted from the moment the 
blood appears. The apparatus for blood drawing consists of a 
very sharp needle connected by means of a 3 to 4 em. rubber 
tube to a glass pipette of about 0.5 cm. bore. The pipette and 
the rubber have a film of sodium oxalate crystals in them. This 
is obtained by wetting the interior with a saturated solution of 
oxalate, which is dried with a current of air. In drawing the 
blood one puts the upper end of the pipette into the mouth (some 
5 It might be more logical to start counting the pulse a half minute before 
the blood appears. However, the pulse rate usually keeps almost constant 
under the procedure if it is skilfully done. 
