272 DISEASE CONTROL 



and a highly bacteriostatic action against some of the most common and 

 destructive bacteria with which man may become infected. It was pos- 

 sible to maintain a bacteriostatic concentration of penicillin in the blood 

 without causing any toxic symptoms. 



Animal Experiments. In animal experiments it was established 

 that penicillin is an effective chemotherapeutic agent against pneumo- 

 cocci, including sulfonamide-resistant types. It is superior, in staphylo- 

 coccus infections, to bacteriophage, sulfa drugs, and specific antitoxins 

 (468). In experiments with S. aureus, a survival ratio of 2: i was ob- 

 tained in favor of penicillin as compared with sulfathiazole, correction 

 being made for the survival of control mice. Penicillin, when adminis- 

 tered subcutaneously, intravenously, or intraperitoneally, was also 

 found to be effective against hemolytic streptococci. Generalized staphy- 

 lococcal infections were cured by penicillin and local lesions healed 

 during parenteral administration. The best method for administering 

 penicillin is by the intramuscular route at 3-hour intervals j the blood 

 should contain enough penicillin (15,000 O.U. dose) to inhibit the 

 growth of the infecting agent. Intraocular infection caused by D. fneu- 

 fnontae was checked by local treatment with penicillin in solutions of 

 0.25 and 0.1 per centj the application was continued for 2 to 4 days 



(817). 



Since penicillin readily loses its activity in an acid solution, it is used 

 in the form of the sodium salt. Rabbits excreted in the urine as much as 

 50 per cent of the penicillin after intravenous injection, but less than 

 20 per cent after administration into the intestine j some excretion took 

 place in the bile. The penicillin could not be detected in the blood 

 within one-half hour after administration. Cats differed in this respect 

 from rabbits, since they maintained an antibacterial concentration of 

 penicillin in the blood for at least 1.5 hours after subcutaneous or intra- 

 venous injection, and for at least 3 hours after intestinal administration. 

 They differed also in excreting about 50 per cent of the penicillin in the 

 urine, even when the substance was injected into the intestine. In this 

 respect man appeared to resemble cats more closely than rabbits. 



A comparison of antibiotic agents against the anaerobes causing gas 

 gangrene placed tyrothricin in first place, followed successively by peni- 

 cillin, the sulfa drugs, and other antibiotic agents; however, in vivo 



