16 THE BACTERIOPHAGE AND ITS BEHAVIOR 



touched to the surface of a plaque or to the periphery of the plaque, 

 and then places the culture at any temperature whatever — ^room or 

 incubator — ^one never observes any transformation. For any length 

 of time whatever the culture as such retains its normal appearance. 

 Microscopic examination shows, except at the point touched, that 

 in all other portions of the culture the micrococci retain their normal 

 form and are never transformed into granules. Indeed, granule forma- 

 tion occurs nowhere. 



As is evident, the phenomenon observed by Twort and the phe- 

 nomenon of bacteriophagy present two entirely different aspects. In 

 the first there is the transformation of the bacteria into fine granules, 

 a "breaking down" according to Twort himself, that is, a bacteriocly- 

 sis. While when bacteriophagy takes place there is a total dissolution 

 of the bacterial cells, leaving no solid residue visible under any mag- 

 nification of the microscope. 



Gratia^^^'^^^ beheved that he had proof of the similarity of the two 

 phenomena when he stated that he had isolated from vaccinal pulp 

 a principle causing the phenomenon of bacteriophagy with all of its 

 characteristic manifestations, such as I have described them. As a 

 matter of fact, Gratia proved precisely the opposite, that is, he showed 

 that the two phenomena are necessarily different. One might admit 

 a priori that the phenomenon of bacteriophagy might be manifested 

 under different aspects in accord with the bacterium against which it is 

 directed, that is to say, that it might be able to effect the detailed 

 process as I have described it when it takes place in a culture of B. 

 dysenteriae, B. typhosus, B. coli, B. pestis, B. proteus, Pasteurella, 

 Vibrios, etc., and that it might occur under the form described by 

 Twort when acting upon cocci. But Gratia has demonstrated that 

 this is precisely what is not the case, but that on the contrary, under 

 the influence of the bacteriophage, the staphylococcus undergoes a 

 typical bacteriophagy, identical in all respects to that of other bacteria. 



The sole conclusion to be drawn from the work of Gratia is that 

 staphylococci (and undoubtedly other bacteria as well) are capable of 

 presenting two "diseased states;" the one consisting of a fragmenta- 

 tion showing the characters described by Twort, the other expressing 

 itself by a total dissolution. And for the latter, the distinctive mani- 

 festations are not simply different from those of the first, but quite 

 exclusive. In the vaccinal lymph may be found, accidentally, the one 

 or the other of the "principles" which cause these phenomena. There 

 is, indeed, nothing impossible in the idea that they may co-exist in a 



