INTRODUCTION 



Bacterial viruses were discovered in 1915, when F. W. Twort (149) isolated 

 a filtrable virus which produces a "glassy transformation" of micrococcal 

 colonies during their growth on an agar surface. Twort's paper remained 

 relatively unnoticed, until two years later F. d'Herelle (64) published his own 

 observations on a filtrable agent, the "bacteriophage," capable of serially trans- 

 missible lysis of growing cultures of enteric bacilli. D'Herelle's announcement 

 caused an immediate sensation among medical bacteriologists, since the 

 bactericidal properties of the bacteriophage oflFered promise of a generalized 

 prophylaxis and therapy of bacterial diseases. Within two or three years of 

 the publication of his first paper, d'Herelle had carried out many incisive 

 experiments which allowed him to recognize the essential aspects of these 

 bacterial viruses. 



Twort and d'Herelle did not remain the only bacteriophage workers for 

 very long, and the study of bacterial viruses rapidly became so popular that 

 most of the leading bacteriologists of the decade following the first World 

 War tried their hand at it. This soon led to a number of violent controversies 

 concerning the nature and mode of action of bacteriophages. Some of these 

 controversies were aired at a discussion on the bacteriophage organized by 

 the British Medical Association at its Glasgow meeting of 1922. The presenta- 

 tions which d'Herelle, Twort, Bordet, and Gratia prepared for this meeting 

 form the first paper of this collection. In his discussion, d'Herelle demonstrates 

 the self-reproducing, or viral, character of the bacteriophage, a view for which, 

 as is evident from the remarks of Bordet and of Gratia, he had been under 

 attack. Gratia's discussion, however, rectifies two errors of d'Herelle: the claim 

 that the phenomena discovered by Twort and by d'Herelle are fundamentally 

 difiFerent and the assertion that all bacteriophages represent the same antigen. 

 In 1926, d'Herelle (65) thus summarized his earlier findings on the multi- 

 plication of bacterial viruses: "The first act of bacteriophagy consists in the 

 approach of the bacteriophage corpuscle toward the bacteria, then in the 

 fixation of the corpuscle to the latter . . . The bacteriophage corpuscle pene- 

 trates into the interior of the bacterial cell. When, as a result of its faculty of 

 multiplication, the bacteriophage corpuscle which has penetrated into the 

 bacterium fonns a colony of a number of elements, the bacterium ruptures 

 suddenly, liberating into the medium young corpuscles which are then ready 

 to continue the action." 



The first workers to study in some detail the initial step in bacterial virus 



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