BEHAVIOR OF BACTERIOPHAGE IN EPIDEMICS 503 



tations, constitutes a defense of the organism in septicemias. In 

 reality, whatever may be the infection, the pathogenic bacterium always 

 gets into the intestine. Let us take a localized disease, cerebrospinal 

 meningitis, for example. We know that the initial symptom is a rhino- 

 pharyngitis and that even healthy subjects who have been in contact 

 with a patient often carry the specific organism in the nasopharynx. 

 There can be no doubt but that a fair number of the meningococci 

 present in the rhino-pharynx are swallowed and pass into the intestine. 

 It is needless to insist on this, that, aside from a few rare exceptions to 

 which we will later return, whatever may be the disease under con- 

 sideration, the portal of entrance of the virus is either the buccal route 

 or by way of the respiratory tract. In either case the ingestion of 

 organisms is, it might be said, obligatory. The pathogenic bacterium 

 is always at some time in contact with the intestinal bacteriophage, 

 this organism therefore is thus able to adapt itself to the bacteriophagy 

 of the bacterium and to acquire a virulence. 



In the particular case of barbone the pathogenic bacterium is found 

 freely disseminated through the exterior world in contaminated regions. 

 In an epizootic zone I have been able, in two different trials, to isolate 

 it from the mud of a marsh where the buffaloes were accustomed to 

 bury themselves. This is but natural since the bacterium of barbone 

 is found in the intestinal tract of sick animals or of those which have 

 succumbed. The ingestion of the pathogenic bacterium by the ani- 

 mals which remain immersed for whole hours in a mire containing these 

 organisms is necessarily frequent. If the animal which ingests them 

 has an erosion at any point in the digestive tract it is susceptible to infec- 

 tion. Otherwise the bacteria reach the intestine and come within the 

 range of the intestinal bacteriophage which can then acquire a virulence 

 for the virus. If this takes place the animal is thenceforth protected 

 from the infection and becomes a carrier of the virulent bacteriophage. 

 A diseased animal propagates his disease; an animal in a resistant con- 

 dition propagates his immunity (d'Herelle and Le Louet''^^). 



3. BUBONIC PLAGUE 



Through a lack of favorable circumstances it has not been possible to 

 follow the evolution of the intestinal bacteriophage in man affected 

 with plague. The few cases that have been examined have all been 

 fatal, and at no time could the intestinal bacteriophage be shown to 

 have the least virulence for B. pestis. The activity in these cases 

 remained restricted to B. coli. However, the stools of two convalescent 



fsz: i I- t B R A II 



