INTRODUCTION 17 



single specimen. Quite commonly two principles, the causes of dif- 

 ferent phenomena, may be found together in the same medium. I 

 have isolated from vaccinal pulp at two different times cocci pre- 

 senting the phenomenon described by Fleming.* May one say that 

 this phenomenon is bacteriophagy, simply because the susceptible 

 coccus occurs in vaccinal lymph? 



Incidentally, those authors who have likened the phenomenon of 

 bacterioclysis of Twort to the phenomenon of bacteriophagy have re- 

 stricted themselves to affirmations only, without offering any supporting 

 proof whatever. I am certain that, with their attention being attrac- 

 ted to this point, should they wish to solve the question they will only 

 have to read the paper by Twort on one hand, and on the other perform 

 a few experiments upon the bacteriophagy of the staphylococcus, 

 and for this a suitable bacteriophage is available to everyone. I 

 believe that all will be in accord with me in the view that if the prin- 

 ciple discovered by Twort and the bacteriophage are identical, when 

 both are acting upon the same bacterium, the staphylococcus, and under 

 identical conditions as to medium and temperature, they ought to 

 incite identical phenomena. If these phenomena are different, as they 

 actually are, it can only be because the principles differ. 



When these authors have themselves made these observations, I 

 trust that they will be willing to distinguish between the two phe- 

 nomena, and to employ the term "phenomenon of Twort," or better 

 the "phenomenon of bacterioclysis" to the bacterial fragmentation 

 presenting the characteristics described by Twort, and the term 

 "phenomenon of bacteriophagy" to the dissolution of bacteria present- 

 ing the characteristics which I first described. 



In concluding, it may be remarked that from the very beginning I 

 have considered the arguments which I have here mentioned and 

 which show the dissimilarity of the two phenomena.^^r These considera- 

 tions were further developed in the book "The Bacteriophage, Its 

 Role in Immunity." They were again repeated at the meeting of the 

 British Medical Association in 1922, a meeting attended by Twort 

 also, who confined himself to simply repeating the statements of his 

 paper of 1915,®"® affirming that the two phenomena were similar, but 

 without discussing, or even aUuding to, the arguments which I had 

 advanced in opposition to his point of view. Again I returned to the 



* Fleming, A., and Allison, V. D. — Further observations on a bacteriolytic 

 element found in tissues and secretions. Proc. Roy. Soc, Lond., 1922/23, 5^6, 

 142. 



