THE PARADYSENTERY BACILLI 261 



SIMMARY. The great majority of the bacilli which have been 

 isolated from cases of dysentery not due to amoebae, and which must 

 be considered as being exciting factors in that disease, are included in 

 three distinct varieties or types. This at least is true for the many 

 cultures which we have isolated or obtained from others. 



The type most frequently found in severe epidemics is that of the 

 first culture isolated by Shiga. Bacilli identical in biochemical and 

 agglutinating characteristics with this bacillus have been isolated from 

 cases of dysentery in many parts of the world. None of the bacilli 

 belonging to this type produce indol, except, perhaps, in a trace, or 

 ferment mannite, maltose, or saccharose. Animals injected with this 

 type produce specific agglutinins for this type in abundance and only 

 very little that combines with the others. 



The second type ferments mannite with the production of acid, but 

 does not split maltose or saccharose in peptone solution or agar. 



It produces indol. Animals, after inoculations with it, develop 

 immune bodies and agglutinins specific for the type. They also develop 

 in considerable proportion immune bodies and agglutinins which have 

 affinity for the bacilli of Type III. and to a slight extent for Type I. 



The third type is nearest to the colon group, since it not only produces 

 indol and actively ferments^mAHTiite, but also acts energetically upon 

 pure maltose and feebly upon saccharose. 



Animals injected with this type develop specific immune bodies and 

 agglutinins, and also abundant immune bodies and agglutinins which 

 have an affinity for the bacilli of Type II. and for many bacilli of the 

 colon group. For Type I. these substances are but slightly developed. 



These two mannite fermenting types are widely scattered over the 

 world, and certainly cause characteristic cases and epidemics of dysen- 

 tery, although on the average the disease caused by them is milder 

 than when due to the Shiga bacillus. One or the other of these two 

 types also appear at times in small numbers in mixed infections where 

 dysenteric symptoms are almost or entirely absent. 



Although the majority of bacilli obtained have had the characteristics 

 of one of the above types, still bacilli have been found in isolated cases, 

 .which, although agreeing in biochemical characteristics with one of 

 the three, nevertheless differed in producing different specific agglutinins. 

 A few bacilli have also been met with which differ slightly in biochemical 

 as well as agglutinating characteristics. 



It seems, therefore, that these three types should be considered as 

 the characteristic representatives of three groups. 



In consideration of all the above facts, it seems to us incorrect to 

 name the mannite-fermenting groups as pseudodysentery bacilli. If 

 we call them all dysentery bacilli, we must classify them as dysentery 

 bacilli of the Shiga group, of the group fermenting mannite, but not 

 maltose, and of the one fermenting both mannite and maltose. 



This manner of differentiating the groups would be very confusing, 

 and it seems to us more convenient, and better, to restrict the name 

 dysentery to bacilli having the characteristics of the bacillus isolated 



