446 BACTERIOLOGY. 



had no agglutinating action upon typhoid bacillus, has 

 revealed a group of bacilli which differ from bacillus 

 typhosus in certain important particulars. These bac- 

 teria possess characters which are intermediate between 

 those of bacillus typhosus and bacillus coli, some resem- 

 bling more closely the former, others the latter, and for 

 these reasons they have sometimes been denominated the 

 intermediate 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 ter- 

 minated 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 varia- 

 tions that it is probable the pathology of different cases 

 also varies with the particular type of organism causing 

 the infection. 



Buxton l was one of the first to make a careful com- 

 parative study of the morphology and biology of this 

 group of organisms. He classifies the intermediary 

 group of organisms in the following manner : 



" Paracolons : those which do not cause typhoidal 

 symptoms in man. A group containing numerous dif- 

 ferent members, but culturally alike. 



" Paratyphoids : those which cause typhoidal symp- 

 toms. 



1 Buxton : Journal of Medical Kesearch, 1902, vol. viii., p. 201. 



