ANDRE LWOFF AND ANTOINETTE GUTMANN 



tides. One can thus compare a lysogenic bacterium to a healthy carrier of germs. 

 What constitutes the particularity of lysogenic bacterium is that they per- 

 petuate a potentially lethal character. The expression of this character, which 

 can be induced by exogenous factors, involves the death of the bacterium. 



• bacteriophage 

 o probacteriophage 



C^'y-induction(J^^^nkction.^r^^ 



*T I \ 



• • . :• ••• 



CZIJ 



J 



c^ 



Diagram showing the evolution of bacteriophage and probacteriophage 

 {prophage) in sensitive and lysogenic megaterium bacilli. 



Both in the case of the sensitive bacterium, as well as in the case of a resistant 

 bacterium, the penetration of the bacteriophage is followed by a disappearance 

 of the infectious character. In both cases, the infectious corpuscle is not re- 

 generated until a short time prior to the bacterial lysis. In both cases, finally, 

 the multiplication of the bacteriophage involves the lysis of the bacterium. 

 But in the case of a sensitive bacterium the penetration of the bacteriophage and 

 its transformation into a non-infectious form is followed immediately by an 



329 



