238 PUBLIC HEALTH BACTERIOLOGY 



then increased alkalinity is produced. The Shiga-Kmse 

 group produce no indol, but the Flexner group do. Short 

 rod, non-motile, non-liquefying, non-Gram-staining, aerobe 

 and facultative anaerobe. 



Bacillary dysentery is an ulcerative colitis with little ten- 

 dency to form liver abscess. It is spread like enteric fever, 

 and is a scourge of armies as it formerly was of asylums. 

 Animals are easily killed by injection, but show no charac- 

 teristic lesions in the intestine, though the latter have been 

 obtained by feeding experiments. The Shiga-Kruse bacilli 

 form a soluble toxin which is very fatal to rabbits, and is 

 resistant up to 70 C. This toxin causes profuse diarrhoea, 

 and later paralysis, when injected intravenously into 

 rabbits, being apparently excreted by the colon and caecum. 



Similar bacilli have been isolated in the summer diarrhoea 

 of infants. 



An anti-toxic serum has been prepared from horses. 



B. Fsecalis Alcaligenes resembles B. typhosus 

 morphologically and culturally, but is non-pathogenic. 



Cultures. Gives a luxuriant growth on potato ; forms 

 no acid with glucose, but alkali with milk whey and 

 mannite. It is an occasional inhabitant of the ileum and 

 colon. 



Other organisms which have been described in connection 

 with the colon-typhoid-dysentery group are : B. nea- 

 politanus (in a choleraic disease) ; B. acidi lactici, of 

 Hueppe ; B. lactis aerogenes (resembles Friedlaender's 

 diplobacillus), and other bacilli present in milk, which 

 appear in the faeces of milk-fed persons. 



Voges-Proskauer Reaction is not given by B. coli 

 nor by any of the above, but by B. lactis aerogenes, B. cloacae, 

 and B. oxytocus perniciosus. Inoculate glucose-peptone 

 solution and grow for 3 days ; add KOH ; stand for 

 twenty-four hours. Red colour. 



DIFFERENTIATION OF B. TYPHOSUS FROM B. COLI. 



The problem is to find a medium which will favour the 

 development of B. typhosus and B. coli and yet will 

 differentiate them. The usual method is to use coloured 

 media -j- inhibitory agents or favouring agents. 



