TYPHOID 147 



matter of great difficulty. The organism which has given 

 rise to much confusion is the Bacillus coli communis. This 

 bacillus is a constant inhabitant of the intestinal tract and 

 the faeces of both man and animals, and therefore is almost 

 invariably found in all polluted waters. 



In order to ascertain whether the typhoid bacillus is 

 present in any given water, care must be taken that the B. 

 coli commimis is not mistaken for the former. This is a 

 very difficult matter, as the vitality of the B. coli communis 

 is much greater under all conditions than that of the 

 typhoid bacillus. The object is generally attained by the 

 addition of various chemical substances to the nutrient 

 media, which effectually inhibit or destroy the growth of 

 organisms other than the colon and typhoid bacilli. As 

 pointed out by Frankland, such additions have frequently 

 destroyed the typhoid bacillus and left the B. coli communis, 

 owing to its greater power of resistance, alone, master of the 

 field. 



According to many authorities, notably Messrs. Eoux 

 and Eodet, there is reason to believe that the B. coli 

 communis, under certain conditions, such as growth in 

 sewage, etc., assumes a pathogenic character, and gives rise 

 to a disease which is clinically undistinguishable from 

 enteric fever. This view is borne out to a great extent by 

 the fact that water contaminated with faecal matter may be 

 instrumental in causing typhoid fever without the actual 

 access of the specific bacillus, as cases are on record where 

 water long known to be polluted has acquired the property 

 of conveying typhoid without the previous known con- 

 tamination from a specific case of the disease. This is in 

 accordance with the well-established fact that in some 

 places enteric fever, once endemic, has disappeared upon 

 the substitution of a pure for a contaminated water-supply, 

 or the provision of adequate bacterial filtration. 



