STAGES IN PHAGE MULTIPLICATION 167 



draw conclusions from these experiments based on the assumption 

 that there was no lysis from without, but this seems doubtful. 



In still other experiments it appears that homologous super- 

 infecting phage does not cause a second leakage. This could be 

 explained by exhaustion of acid-soluble phosphorus during the 

 first leakage coupled with resistance to lysis from without. The 

 authors postulate instead a "resealing reaction." Since this re- 

 action is supposed to explain resistance to lysis from without and, 

 in fact, faulty penetration by superinfecting phage, the two 

 interpretations are not very different. 



It seem.s reasonable to conclude, in agreement with Puck and 

 Lee, that normal infection causes leakage of some cellular con- 

 stituents, incidentally to penetration of the cell wall by phage, 

 and that the holes have to be repaired before viral growth can 

 proceed. All of the facts discussed above show that the repair 

 does not merely restore the cell surface to its initial condition, 

 but confers on it several new properties. 



The ideas of Puck and Lee serve to unify numerous observa- 

 tions, as already discussed. Penetration of the cell wall causes 

 damage detected as leakage of low molecular weight constituents 

 and possibly others, and causes a slight fall in the turbidity of the 

 bacterial suspension. This damage is limited in some way, since 

 it is independent of multiplicity of infection in the absence of lysis 

 from without. The damage is accompanied by an overcompen- 

 sating repair process that explains resistance to lysis from without 

 and exclusion of superinfecting phage. The two processes are in 

 competition : lysis from without results when the repair mecha- 

 nism is overwhelmed by excessive damage. The repair mecha- 

 nism, at least, depends on cellular metabolism. Metabolic in- 

 hibitors favor lysis and magnesium ions oppose it. 



Puck and Lee (1954) attributed leakage to holes produced by 

 bacterial enzymes, largely by analogy between lysis from without 

 and effects of certain synthetic polyamino compounds that cause 

 lysis. The following work does not contradict this view but sug- 

 gests the participation of phage enzymes as well. 



Barrington and Kozloff (1956) and Koch and Weidel (1956b) 



