ACTIVE FROM INACTIVATED BACTERIOPHAGE 109 



curves for low multiplicities, up to :*; = 0.5; for higher multiplicities they fall 

 below the corresponding curves for y calculated for the same number of units. 

 We can actually find, for each value of x, a curve for y — for the same n but 

 corresponding to a lower x — which fits the experimental curve. The correspond- 

 ing theoretical curves are drawn in figures 5-7. This indicates that groups of 

 more than two particles collaborate in reactivation as if they consisted of a 

 lower but definite number of particles. 



It is interesting to notice that the systematic deviation from theory for 



W I 



Fgure 4.— Same as figure 2, for phages T6 and T6r. The theoretical curves for 

 y correspond to n = 30. 



263 



