192 



NATURE OF ANTIBIOTIC ACTION 



TABLE 26. BACTERICIDAL EFFECTS OF PENICILLIN, GRAMICIDIN, AND 

 TYROCIDINE UPON S. HEMOLYTICUS 



NUMBER OF VIABLE ORGANISMsf 



At At At 



At I hour 3 hours 7 hours 24 hours 



4,300 2,650 420 o 



2,430 1,140 7 2.4 



0.1 o 00 



From Dawson, Hobby, Meyer, and Chaffee (164). 



* 10 Y of each preparation was added to i milliliter ot culture. 



t In thousands per milliliter. 



TABLE 37. BACTERIOSTATIC AND BACTERICIDAL ACTION OF FUMIGACIN 

 AND CLAVACIN 



From Waksman, Horning, and Spencer (935). 



* Staphylococcus cultures and gram-negative pathogens incubated at 37° C, others at 28° C. 



t Units of activity ^ dilution in plate or tube inhibiting growth completely. 



% Micrograms required to kill bacteria in i milliliter portions of 6-hour-old cultures. 



§ Water saturated solution used. 



If Crude mother liquor, from which 2 lots of crystals were removed on basis of dried material in 



solution. 



II Incomplete sterilization of culture even in 24 hours 



