THE DYSENTERY BACILLI 257 



The German observers considered the Shiga type as the only one 

 which had established. its causal relation to acute dysentery, while the 

 American observers generally considered both types to have equal 

 standing and some 1 of them considered these differences as not impor- 

 tant and perhaps not permanent. This latter opinion seems to have 

 been held by Shiga. 2 



We took up the investigation at this point with the object of care- 

 fully studying the bacilli isolated by us from acute dysentery, which 

 occurred in a number of widely separated epidemics. We hoped thus 

 to determine whether the bacilli exciting acute dysentery in the Eastern 

 States belonged to a few distinct types or were divided into a large 

 number of varieties. 



In the most extensive epidemic that has recently occurred in 

 the region of New York City there were in all some 500 cases 

 of acute typical dysentery. Whole families were attacked with the 

 disease. 



The majority of the cases were of moderate severity, the dysenteric 

 discharges lasting from one to two weeks. There were a number of 

 light cases, but all had dysenteric stools containing mucus and blood. 

 The mortality was about 6 per cent. Judging from the cases investi- 

 gated by us, over one-half of those attacked seem to have been infected 

 by the Shiga type, and these were, as a rule, the most severe cases. 

 Most of the cases in two severe, though localized, epidemics in a Penn- 

 sylvania town and at Sheepshead Bay were also due to this type. The 

 mortality was higher in these epidemics. The facts published abroad 

 also indicate that this variety has been found in the chief epidemics in 

 Europe and Asia. The bacilli isolated in the severe epidemic of dysentery 

 reported by Vedder and Duval (at New Haven, Conn.) were chiefly of 

 this type. We have never yet succeeded in isolating bacilli which had 

 all the characteristics of the Shiga variety from any diarrhoea cases in 

 which no dysenteric symptoms appeared. 



We turn now to the mannite fermenting varieties, whose relationship 

 to dysentery is still doubted by some. 



The cultures isolated by us from over 40 cases were found to fall 

 largely into two distinct types, one of which differs from the Shiga 

 bacillus more radically than the other. 



The variety nearer to the Shiga bacillus has the characteristics of 

 the culture, which was isolated by us at Seal Harbor, Maine, in 

 August, 1902. The other variety is represented by the Flexner 

 Philippine type. 



The first* type differs from the Shiga bacillus in its agglutinating 

 characteristics and in that it produces considerable indol in peptone 

 solution and ferments mannite with the production of acids. The 

 second type differs in these points and in addition that in its aggluti- 

 nating characteristics ferments saccharose and chemically pure maltose 

 in peptone solution. 



i University of Pennsylvania Medical Bulletin, July and August, 1983. 

 * Zeitschrift f. Hygiene u. Infectionskrank., 1902, xli., 356. 

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