The PAPERS of Kildeberg and Engel and of Nelson and Riegel continue what has been called, inaccurately, "The Great Transatlantic Acid-Base Debate" betsveen two schools of acid-base physiology. Historically at least, these can be called the Continental and Anglo-American Schools and their current dispute a war of words. We will sketch their beginnings, describe some of their differences, and indicate the importance of the distinction between fundamental and derived measurement.
The Continental School was probably founded by Hasselbalch, who in 1916 began the apparently never-ending search for a chemical index of a "metabolic component," i.e., a number indicating the quantity of non-volatile acid added to or lost from the body-"corrected" for respiratory effects. Hasselbalch index was typical of the genre because it required exposing a blood specimen in vitro to known CO2 gas mixtures and was called a "reduced hydrogen ion concentration." His successors have tended to work meticulously in chemical laboratories, to give special names to defined magnitudes, and to incorporate these into logical formulations. One example was that of Singer and Hastings, which was based on a thoroughgoing study of blood as a physicochemical system at various states of equilibrium outside the body. Another recent and carefully developed one is that of Siggaard-Andersen. Despite this and other authors warnings, this school formulations are subject to abuse perhaps especially by those who assume that an "Astrup determination" is a substitute for clinical judgement.
The other school is less systematic, its members being more often physiologists or physicians than physical chemists.
Vilfredo Pareto Philosophical Theory, Action & Residue with its Classification