380 



GROWTH OF BACTERIOPHAGE 



We at first suspected that the fluctuation in burst size was con- 

 nected with the time of the burst, in that early bursts were small and 

 late bursts big, and the fluctuation was due to the experimental 

 superposition of these. However, measurement of a large number of 

 bursts, plated at a time when only a small fraction of the bursts had 

 occurred, showed the same large fluctuation. We then suspected that 

 the particles of a burst were not liberated simultaneously, but over an 

 interval of time. In this case one might expect a greater homogeneity 



TABLE III 



Fluctuation in Individual Burst Size 

 97.9 per cent of phage attached to bacteria in presence of excess bacteria (10 

 minutes), this mixture diluted, and samples incubated 200 minutes, then entire 

 sample plated with added bacteria. 



in burst size, if measurements were made at a late time when they are 

 at their maximum value. This view also was found by experiment 

 to be false. 



The cause of the great fluctuation in burst size is therefore still 

 obscure. 



DISCUSSION 



The results presented above show that the growth of this strain of 

 phage is not uniform, but in bursts. These bursts though of constant 



52 



