“…Isotonic solutions of procaine (Hoechst, India), 0.5, 1.0 and 2%, were made by first dissolving the procaine in 8 ml. of distilled water for each 0.3 g and later making up the volume with artificial cerebrospinal fluid to the desired strength-a procedure recommended by Sprowls (1949) for preparation of isotonic solutions with 0.9% saline. For comparison the procaine was diluted in some experiments with artificial cerebrospinal fluid without reference to isotonicity.…”