280 DISEASE CONTROL 



ministration and amounts required depend largely upon the suscepti- 

 bility of the infecting strain of the organism. 



Clavacin (Claviformin, PatuUn) 



The treatment of common colds that were prevalent in an English 

 naval establishment by the use of clavacin in the form of nasal sprays or 

 snuffed up by hand gave 57 per cent complete recovery in 48 hours, as 

 compared with 9.4 per cent for the controls j no ill effects were observed 

 (744). These results were not confirmed, however, the conclusion hav- 

 ing been reached that, compared with the natural evolution of the dis- 

 ease, clavacin has no demonstrable effect on the course of a cold (876). 

 This substance also proved to be unsatisfactory for the treatment of bo- 

 vine mastitis by udder infusion (718). In general, it is too toxic to be of 

 therapeutic usej it acts as a tissue poison and has other undesirable 

 pharmacological effects (90). To what extent the antifungal action of 

 clavacin can be utilized for controlling fungus infections remains to be 

 determined, since it is known to inhibit the growth of Trichophyton 

 gyfseum in concentrations of 0.02 per cent and in certain cases even 

 0.0 1 per cent. It had only a slight effect upon other fungi in 0.04 per 

 cent concentration (416). 



Tyrothricin 



Dubos (203) reported that 0.002 mg. of gramicidin, one of the two 

 chemical constituents of tyrothricin, when injected intraperitoneally 

 into white mice, exerted a therapeutic action against experimental peri- 

 tonitis caused by pneumococci and streptococci (Table 45). This sub- 

 stance was found to be effective against five different types of pneumo- 

 cocci, eleven types of group A streptococci, and three strains of group C 

 streptococci. It was, however, almost completely ineffective when ad- 

 ministered into animal tissues by the intravenous, intramuscular, or 

 subcutaneous route, because of its lack of activity under these conditions, 



Tyrothricin exerted a lethal action in vitro on 1 8-hour broth cultures 

 of S. hemolyticus, S. aureus, and C. diphtherias, in a final dilution of 

 1 : 1,000,000; freshly isolated strains of meningococcus were affected in 

 a dilution of i:i00,000 (841). Two monkeys which carried in the 

 nasopharynx and throat gram-positive hemolytic streptococci and gram- 



