To the Editor.
—I read with interest the letter by Neiberger1 as this issue was raised before in the 1970s.2I believe that there are typing errors in the sentence, "In the days of Arrhenius, Severinghaus, and Henderson-Hasselbalch...."S. A. Arrhenius (1859-1927) was a Swedish chemist and physicist.3 L. J. Henderson (1878-1942) was a Boston, Mass, physiologist.4 H. A. Hasselbalch (1874-1962) was a Copenhagen biochemist.4 J. W. Severinghaus is the inventor of the commonly used Stow-Severinghaus CO2 electrodes and is a distinguished professor in anesthesiology at the University of California, San Francisco. Severinghaus does not belong to the bygone era.I think Neiberger really meant to type, "In the days of Arrhenius, Sorenson, Henderson, and Hasselbalch...." S. P. L. Sorenson (1868-1939) was a Copenhagen biochemist who invented the pH system in 1909.3
Wu A. More RIpH. JAMA. 1992;267(15):2035. doi:10.1001/jama.1992.03480150041020