114 BACTERIOLOGICAL EXAMINATION OF WATER. 



ten to fifteen minutes, cooled, and cultivated anserobically in 

 Buchner's tubes. If the typical changes are seen in any one 

 of the milk tubes, the presence of B. enteritidis is probable ; 

 but to obtain a decisive result the pathogenic action of the 

 organism must be tested by injecting 1 c.c. of the whey into 

 a guinea-pig. The fact that Botkin's bacillus butyricus exactly 

 resembles the B. enteritidis, culturally and morphologically, 

 renders the animal experiment absolutely imperative ; unfortu- 

 nately, the necessity of resorting to an animal experiment 

 militates against the extensive use of this test in ordinary 

 bacteriological examinations for hygienic purposes. Still, if 

 the typical appearances in milk are found in conjunction with 

 the presence of typical B. coli in a small quantity of the water, 

 the fact of sewage contamination may be considered sufficiently 

 proved for all practical purposes. 



