To the Editor.— In their communication "The pH and Acidity of Intravenous Infusion Solutions" (215: 1937, 1971), Lebowitz et al echo the concern of Cronk1as well as the reassurances of Spodick et al2with respect to the acidity of intravenous infusions. The problem is just as relevant to drugs commonly injected intravenously (Table 1). Since these drugs and the infusion solutions investigated by Lebowitz et al have no ionization of their own, the free hydrogen ions giving the acid pH derive from a little carbonic acid ionization which has a buffering capacity amounting to essentially zero. On coming into contact with the highly buffered blood, the change in pH is not of any consequence. As an example, we mixed 10 ml of heparinized whole blood with 2 ml of ketamine (Ketaject) of pH 4.40 anaerobically, and found the pH had changed to 7.12. Thus, the average dose