108 

 W I 



S. E. LURIA AND R. DULBECCO 



10" 



10" : 



10" 



I0" 4 -. 



Figure 3. — Same as figure 2, for phages T4 and T4r. The theoretical curves 

 for y correspond to n = 15. 



vation, while steadily increasing, does not keep pace with the theoretical 

 function y. The cooperation within groups consisting of more than two par- 

 ticles is not as successful in bringing about reactivation as required by the 

 simple theory, whereas pairs of particles apparently collaborate with an 

 efficiency of one hundred percent. 



The deviation for higher multiplicities is reflected in the curves of figures 5-7. 

 The curves for w as a function of the dose are very close to the theoretical 



281 



