THE COLON-TYPHOID SEEIES 339 



fact that in certain cases, clinically typhoid, the blood serum 

 of the patient did not acquire the property of agglutinating 

 true typhoid bacteria, but that organisms could be isolated 

 from the feces of the patients which would be agglutinated 

 specifically by their blood serum. In recent years there have 

 been recorded many instances of epidemics caused by the 

 paratyphoid bacilli. The disease is transmitted in the same 

 manner as is typhoid fever and methods of prevention are 

 identical. These will be discussed at greater length under 

 the heading of typhoid. 



The bacteria causing paratyphoid fever of the two types 

 can be differentiated from each other and from other mem- 

 bers of this subgroup only by their physiological and sero- 

 logical characters. 



Bacterium pulloeum 



This organism has been described as the specific cause 

 of the disease white diarrhea in young chicks. It is similar 

 in all but a few of its physiological and serological reactions 

 to other members of this group. It is a nonmotile rod. 



The disease is characterized in chicks by emaciation and 

 white diarrhea. The organism may be isolated in pure 

 culture from the internal organs, particularly from the 

 liver. It has been found by Rettger that pullets which 

 recover from this disease frequently develop into hens 

 which are bacillus carriers, that is, the organisms remain in 

 the ovaries and are present in the eggs laid. The chick, 

 therefore, in such cases is infected before hatching. A few 

 such chicks among those hatched by an incubator or present 

 in a brooder will rapidly infect the other chicks. Infected 

 hens may frequently be detected by means of the agglutina- 

 tion reaction, that is, their blood serum contains the agglu- 

 tinin specific for the organism and the precentage of loss 

 among chicks may be materially reduced by weeding out 

 hens which react. The disease has been the occasion of very 



