MTIOLOGY 



1845 



war; and this factor appears to be more potent than any cHmato- 

 logical cause, and, indeed, may be the principal reason why the 

 disease is so prevalent in the tropics, though the high atmospheric 

 temperature of these regions must assist the growth of the organisms. 



etiology. — Bacillary dysentery is brought about by a group of 

 closely allied bacilli which may be separated into several principal 

 types according to their fermentative action on glucose, mannite, 

 maltose, saccharose, lactose. 



I. Shiga-Kruse Type. — Glucose fermented (acid only) ; mannite, 

 maltose, saccharose, lactose not fermented. Agglutinated only by 

 homologous serum. Not agglutinated by normal horse serum. 

 Very toxic to rabbits. 



II. Flexner Type. — Glucose, mannite, maltose fermented (acid 

 only); saccharose not fermented, but there are exceptions; lactose 

 not fermented. Agglutinated by homologous serum and Y serum, 

 and not unfrequently by Shiga serum and, as shown by M. 

 NicoUe, normal horse serum. Non-toxic to the rabbits. 



III. Strong Type. — Glucose, mannite, and saccharose fermented 

 (acid only) ; maltose not fermented. Agglutinated by homologous 

 serum only. Most authorities consider it non-toxic, but the 

 original Strong strain was very toxic to rabbits. 



IV. Hiss and Russell Type. — Glucose and mannite fermented 

 (acid only) ; maltose, saccharose, lactose not fermented. Agglu- 

 tinated by homologous and Flexner serums, at times by Shiga 

 serum and normal horse serum. 



V. Metadysentery [Castellani) Type. — ^Differs from all above 

 groups in fermenting (slowly and acidity only) lactose in addition 

 to glucose. Well agglutinated by homologous seram ; not aggluti- 

 nated by Flexner and Shiga serum. Non- toxic to rabbits. 



For more details on bacteria of the dysentery group the reader is 

 referred to Chapter XXXVI., p. 936. Less important types are Riiffer 

 and Willmore's Bacillus ElTor'No. i, Baerthlein's Bacillus dysenteric^, 

 Shiga's B. dysenteries Tokio, Castellani's Bacillus paradysentericus, etc. 



Hiss divides the dysentery bacilli into four principal groups: — • 

 Group i: Ferments glucose only (Shiga-Kruse bacillus). 

 Group 2 : Ferments glucose and mannite [Bacillus Y) . 



Group 3 : Ferments glucose, mannite, and saccharose (Flexner - Manila 

 bacillus) . 



Group 4: Ferments glucose, mannite, saccharose, maltose, and dextrine 

 (Harris's bacillus, Wollstein's bacillus). 



Leitz, Kruse, and Shiga have called attention to the fact that while the 

 fermentation of mannite is a reliable means of differentiation, not so much 

 importance can be given to the fermentation of maltose, saccharose, and 

 dextrine. 



Lehman and Neumann give the following classification: — • 



1. Shiga-Kruse: No fermentation of mannite, maltose, saccharose, 



2. Flexner: Ferments mannite and maltose. 



3. Strong: Ferments mannite and saccharose. 



4. B.Y. : Ferments mannite; has no action on maltose and saccharose. 



Bahr has noted that the various strains may vary their fermentative 

 character when passing through flies . 



