204 THE BACTERIOPHAGE 



bacteria, and it is only toward the decline of this relapse or of the 

 recrudescence that the virulence of the bacteriophage is sufficient 

 to definitely control the resistance of the bacterium. Here, the 

 activity of the bacteriophage is maintained up to complete re- 

 covery, that is to say, up to the moment when, because of a total 

 destruction of the pathogenic bacteria, the ultramicrobe is no 

 longer able to develop at their expense. 



In all cases, the condition of the patient faithfully registers 

 the vicissitudes of the struggle taking place within the body 

 between the bacteriophage and the invading bacterium. 



AVIAN TYPHOSIS 



The disease 



Avian typhosis is a disease affecting principally the Gallinaceae. 

 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' y 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 surrounding 

 territory were discovered. 



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

 interesting disease. Its study is complicated by the existence 

 of several " paratyphoses" which resemble still 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 agglutinated to titre by an anti- 

 typhoid serum. Aside from this type bacillus there are often 

 found, in the same foci, bacilli presenting different agglutinative 

 and biochemical reactions. The clinical type of the infection 

 which the}- provoke does not differ from that caused by the 



