BEHAVIOR OF BACTERIOPHAGE IN DISEASE 479 



Fejgin204.205 j^^s recently reported some experiments showing that the 

 "invisible virus" of Friedberger and Meissner is nothing other than the 

 filtrable form which B. typhosus assmnes when in symbiosis with the 

 bacteriophage. 



The action of the bacteriophage in disease is very complex, and we 

 will be the more convinced of this as we study other diseases, but what- 

 ever may be its mode, or modes, of action, the whole pathogenesis of 

 the disease and its issue are determined by the behavior of the 

 bacteriophage. 



4. THE BACTERIOPHAGE IN AVIAN TYPHOSIS 



Avian typhosis is a disease affecting principally the Galhnaceae. 

 Despite its frequency it for a long time remained undetected, confounded 

 with chicken cholera. This last disease is, in reality, very rare. In 

 1919, in investigating epizootics for the purpose of testing on domestic 

 animals, which allow of experimentation, the conclusions reached as 

 to the role of the bacteriophage in human dysentery and typhoid, an 

 extended focus of "chicken cholera" was found in the Department of 

 the Aube. In the first examinations the error which had been made 

 became apparent; it was the disease known in the United States as 

 "fowl typhoid," whose existence in France had up to that time been 

 unrecognized. Shortly after this numerous foci throughout the sur- 

 rounding territory were discovered. 



Fowl typhoid, which will here be called fowl typhosis, is a very in- 

 teresting disease. Its study is comphcated by the existence of several 

 "paratyphoses" which resemble stUl more the human typhoid. The 

 pathogenic agent, B. gallinarum Klein, studied by Moore under the name 

 of B. sanguinarium, presents, with the exception of motility, all of the 

 characteristics of the bacillus of Eberth {B. typhosus). It is even ag- 

 glutinated to titre by an antityphoid serum. Aside from this type 

 bacillus there are often found, in the same foci, baciUi presenting differ- 

 ent agglutinative and biochemical reactions. The clinical type of the 

 infection which they provoke does not differ from that caused by the 

 typhoid type. These differing species of bacteria have up to the present 

 been studied only by American workers; Ph. Hadley among others, 

 who describes B. pullorum A, B. pullorum B, B. jeffersonii, B. rettgeri, 

 and B. pfaffi. A discussion of the distinctive characters of these differ- 

 ent bacilli will not be presented here since it would not be germane to 



