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THE EXAMINATION OF MILK 



(iii) Bacterium coli communis and allied organisms. 

 The occurrence of Bact. coli in milk is one of the most 

 important indications of pollution by manure, sewage or 

 dirty water contaminated with faecal matter. 



The characters of the bacterium are given on p. 1 06. 



Besides true typical Bact. coli there are a number of 

 very closely allied organisms commonly met with in 

 faeces and water which is polluted by animal excreta. 

 They are spoken of as " coliform " bacteria, and are 

 regarded as more or less permanent modifications or 

 varieties of Bact. coli, differing only from the type in 

 certain biological characters such as the power of curdling 

 milk, fermentative action on various carbohydrates and 

 production of indole. 



For all of these forms a search should be made in 

 milk : the following table, based on the admirable 

 researches of MacConkey is of great value in diagnosing 

 any organisms of this class which may be isolated. 



CHAEACTEES OF "COLIFOEM" OE3ANISMS. 



