“…The use of oil as a vehicle enables the compound to be dispensed ready for use in a stable form, and further prolongs absorption. From the reports of Hobby, Brown, and Patelski (1948) it appears that in vitro and in laboratory animals it is little if at all inferior to sodium penicillin G, and the persistence of penicillin in the blood of animals following a single injection, which they describe, has been shown to occur in humans by Herrell, Nicols, and Heilman (1947), by Boger, Oritt, Israel, and Flippin (1948), and by Hewitt, Whittlesey, and Keefer (1948). Following a single injection of 300,000 units of procaine penicillin Herrell et al (1947) found detectable amounts of penicillin in the blood of nine out of ten patients after 24 hours.…”