“…Investigations carried out on the serum penicillin concentration of patients undergoing combined penicillin and probenecid treatment (White, Conch, Foster, Galloway, Hunter, and Knight, 1965;Evans, 1966;Schmidt and Roholt, 1965;Cornelius, Schroeter, Lester, and Martin, 1971) have given varying results, probably because of differences in the methods used in combining probenecid with penicillin and the use of different types of penicillin.…”