538 APPLICATION OF METHODS OF BACTERIOLOGY 



BACILLUS PARATYPHOSUS. 



During recent years careful bacteriological examination 

 of cases of continued fever, the blood from which had no 

 agglutinating action upon typhoid bacillus, has revealed a 

 group of bacilli which differ from bacillus typhosus in certain 

 important particulars. These bacteria possess characters 

 which are intermediate between those of bacillus typhosus 

 and bacillus coli, some resembling more closely the former, 

 others the latter, and for these reasons they have sometimes 

 been denominated the intermediate, "near" or "para" 

 group. Some of the organisms isolated from such cases 

 of continued fever resemble very closely bacillus enteriditis, 

 which Gaertner found in cases of meat poisoning. 



The general opinion is that these organisms produce a 

 form of infection sometimes resembling in' many of its 

 clinical characters that produced by bacillus typhosus. 

 The infection, however, is usually of a milder type and 

 only a comparatively small number of cases have terminated 

 fatally, so that the pathology of the disease is not well 

 known. Moreover, the biological characters of the different 

 organisms isolated from cases of paratyphoid fever, as the 

 condition is called, show such wide variations that it is 

 probable the pathology of different cases also varies with 

 the particular type of organism causing the infection. 



Buxton 1 was one of the first to make a careful compara- 

 tive study of the morphology and biology of this group of 

 organisms. He classifies the intermediary group of organ- 

 isms in the following manner: 



" Paracolons : those which do not cause typhoidal symp- 



1 Journal of Medical Research, viii, 201. 



