DYSENTERY 89 



both the soluble and the gaseous forms. However, it retains both 

 viability and virulence for days when deposited on clothing or food. 

 It soon dies out in running water and epidemics of bacillary dysentery 

 due to infected water are probably rare. In sterilized water it lives for 

 many weeks, but in the presence of the usual saprophytic bacteria of 

 water it soon dies out. 



The Flexner Bacillus. Morphologically, culturally and tinctorially 

 this organism is but little different from the Shiga bacillus. It, how- 

 ever, produces indol in peptone cultures more abundantly; produces 

 acid in mannite cultures; rapidly reduces nitrates to nitrites; and 

 elaborates a soluble toxin, either not at all or only in small amount. 

 These differences in function rather than in form, lead to the con- 

 clusion that the two organisms are of different species. The His- 

 Russell organism is a variety or strain of the Flexner bacillus. It 

 produces indol more slowly, reduces nitrates less energetically, and 

 decomposes mannite, but is without action on maltose and saccharose. 

 The Strong organism is even more closely related to the Flexner 

 bacillus and in fact there seems to be no constant differences when 

 many strains of both are studied. The Shiga bacillus with its sub- 

 varieties is known as the dysentery bacillus rich in toxin production, 

 and the others as poor in this product. The latter are found to be the 

 more stabile. They are not so easily overgrown by saprophytic bac- 

 teria; they retain their vitality for a longer time under adverse con- 

 ditions and they are not so easily destroyed by disinfectants. They 

 may persist for many days in drinking water, for many weeks on 

 clothing, and cultures need to be transplanted only every second or 

 third month. 



Rabbits, mice, dogs, goats and horses are highly susceptible to sub- 

 cutaneous, intra-abdominal and intravenous inoculations with these 

 bacteria, especially the Shiga bacillus. Very minute doses introduced 

 by these avenues cause acute fever with paralytic symptoms in the 

 extremities, diarrheic stools with mucus and blood, then a rapidly fall- 

 ing temperature ending in death: Post-mortem examination shows 

 an inflammatory condition of the kidneys, lungs and the mucous mem- 

 brane of the intestinal tract. The bacilli are found in these cases in 

 the stools, in the blood, and in the various organs. With still smaller 

 doses the disease is more chronic and the lesions are more advanced 



