SCIENTIFIC PROCEEDINGS. 



Abstracts of Communications. 

 One Hundred Twenty-first Meeting 



University and Bellevue Hospital Medical College, February 15, IQ22. 

 President Wallace in the chair. 



91 (1838) 



A method for the rapid determination of urea in minute amounts 



of blood. 



By ISRAEL S. KLEINER. 



[From the Department of Physiological Chemistry of The New York 

 Homoeopathic Medical College and Flower Hospital, 

 New York City.] 



This method involves the digestion of urea by urease (Marshall- 

 Van Slyke), the precipitation of the proteins (Folin-Wu), the direct 

 Nesslerization of the filtrate (Myers) and determination of the 

 color in the micro-colorimeter previously described. 1 For this 

 color comparison a wedge, containing 1 per cent, potassium dichro- 

 mate, mounted on a deep yellow ground-glass plate, is used. 



The technique is as follows: A 0.2 c.c. pipette is rinsed with 

 20 per cent, potassium oxalate solution. The residual fluid is 

 blown out well and 0.2 c.c. of blood is drawn up from the pricked 

 finger or ear-lobe and discharged into a small test-tube. The 

 pipette is then rinsed twice with exactly 0.2 c.c. of water and the 

 washings are added to the blood. Three or four milligrams (knife- 

 point) of powdered urease are now added to the blood and, after 

 shaking, a stopper is inserted and the tube is kept at 50 0 for 10 

 minutes or at room temperature for 30 minutes or longer. Then 

 1.0 c.c. of water is added, followed by 0.2 c.c. of 10 per cent, 

 sodium-tun gstate solution and 0.2 c.c. of 2/3 N sulphuric acid. 



1 Kleiner, Journal A. M. A., 1921, lxxvi, 172. 



195 



