The Ammonia Content of the Blood, and Its Bearing on the Mechanism of Acid Neutral- Ization in the Animal Organism

A review of the very full literature upon the concentration of ammonia in blood discloses much confusion and divergence in the reported values. For example, the range of values for the systemic blood of normal dogs is from a few hundredths of a mg. (Folin and Denis, 1) to 5 mg. (MacCallum and Voegtlin, 2) or more of ammonia nitrogen in 100 cc. Even more pronounced are variations in the data of comparable pathological states; yet in many instances the blood ammonia has been determined purely incidental to the investigation of problems of intermediary metabolism, and made the basis for hypotheses whose validity depends upon not only the relative but absolute accuracy of the analyses. With improvements in technique, and a growing appreciation of the inherent difficulties in the estimation of ammonia in blood there has been a preponderant (but by no means uniform) trend to the lower extreme of values, until, according to Myers (3), ‘(there appears to be some question at the present time as to whether ammonia actually exists in the blood.”