For surgical practice, chemical methods of investigation are beginning to have a field of usefulness comparable with the one they occupy in clinical medicine. In gathering data to indicate the character of the operative risk, it has been customary for a long time to employ urinalysis, blood counts, hemoglobin determinations and estimations of the arterial tension. At present it seems advisable frequently to add to these precautionary measures the determination of what has been called the "alkali reserve," for postoperative nausea and vomiting, menacing convalescence, may depend on an acidosis for which the anesthetic is responsible.
The underlying facts regarding the regulation of the equilibrium between the acids and bases of the animal body were contributed by the research of the Haldane school of physiologists, by Hasselbach, Lawrence Henderson and later by others. Under normal circumstances the acid-base equilibrium is remarkably stable; Haldane found that in healthy individuals the balance