BACTERIOSTATIC AND BACTERICIDAL AGENTS 247 



Figure 25. Action of actinomycin on E. coli; death rate in buffer solution. 

 Amounts are given in milligrams of actinomycin per lo milliliters of solu- 

 tion. From Waksman and Woodruff (977)- 



cal nature of this antibiotic agent and of quinones. On the other hand, 

 many of the antibiotic substances produced by fungi are typical qui- 

 nones and act as such. 



By varying the concentrations of disinfectants, the types of curves of 

 destruction of bacterial cells were found (728) to range from linear to 

 an abrupt drop to zero at critical concentrations. This is brought out in a 

 study of the spirocheticidal action of penicillin (Figure 26). 



