650 



INTRACELLULAR GROWTH OF BACTERIOPHAGES. I 



of their experiments differed somewhat from those presented here, tlie loss of 

 infectious centers in their experiments suggested testing whether cyanide could 

 cause a similar loss of infected bacteria in the present procedure. An experi- 

 ment w-as made which was identical with the standard cyanide lysis experiment 



100- 



uj 10- 



« 1.0- 



T4r^AT 37' 



001- 



INFECTEO BACTERIA 



• -ON" 



O -CN~+ T€ 



I0~ 15 20 25 



MINUTES OF INCUBATION IN GROWTH MEDIUM AT 37* 



Fig. 2. The comparative effect of cyanide alone and cyanide plus T6 on singly 

 infected bacteria at various stages in the latent period. 



except that T6 was omitted from one set and included in a parallel set of lysing 

 medium cultures (Fig. 2). As in the case of 5-methyltryptophan, it is seen that 

 cyanide alone caused a loss of infectious centers when added in the early stages 

 of phage growth, although the loss is less than that produced by cyanide and 

 T6 together. Furthermore, in the second half of the latent period, comparison 

 of the two media showed clearly and surprisingly that a definite rise in titer of 

 infective centers occurred even when the lysing agent, T6, was omitted from the 



80 



