BIOCHEMISTRY: A. ROHDE 357 
VIVIDIFFUSION EXPERIMENTS ON THE AMMONIA OF THE 
CIRCULATING BLOOD 
By Alice Rohde 
DEPARTMENT OF PHARMACOLOGY. JOHNS HOPKINS MEDICAL SCHOOL 
Presented to the Academy, May 5, 1915 
The fact that the ammonia content of shed blood under aseptic con- 
ditions increases is well known and is taken into account as much as 
possible by a rapid procedure in methods for the determination of pre- 
formed ammonia. Suggestions as to the source of this slowly Hberated 
ammonia have as yet led to no positive findings. My experiments 
were undertaken to determine whether with aseptic measures the 
formation of ammonia occurs in diffusible constituents of the blood after 
their separation from the non-diffusible constituents according to the 
vividiffusion method of John J. Abel^ and his collaborators. The 
dialysate, obtained when the vividiffusion apparatus was attached to 
the femoral artery and femoral vein of a dog for periods varying from 
three to seven hours, was studied for the production of ammonia in 
excess of that present at the time of dialysis. The results were com- 
pared with those from shed blood under similar conditions. It was 
found that in a dialysate obtained from circulating blood there is no 
liberation of ammonia comparable to that which takes place under 
aseptic conditions in shed blood. 
Milligrams of 
Blood NHj-N per 100 cc. 
Sample taken at close of dialysis 0 . 30 
Sample taken at close of dialysis and allowed to stand 36 hours 0.63 
Dialysate 
Sample after 5| hours dialysis 0.27 
Sample after 7 hours dialysis 0.29 
Sample removed after 7 hours dialysis and allowed to stand 36 hours 0. 28 
The ammonia content of the blood is doubled in twenty-four hours 
while that of the dialysate shows no increase. An equihbrium between 
the ammonia content of the dialysate and of a sample of the circulating 
blood was reached. 
The slowly evolved ammonia has its source therefore in non-diffusible 
constituents of the blood. 
Details of the methods with additional tables appear in the June 
(1915) number of the Journal of Biological Chemistry. 
1 On the removal of diffusible substances from the circulating blood of living animals. 
J. Pharmacol. Exp. Therap., 5, 275 and 611 (1914). 
