TYPES OF BACTERIA FOUND IN MILK 37 



tion, though not so common as the others, is yet not infre- 

 quently found. It is of some importance, however, because it 

 is generally recognized as indicating the presence of fecal 

 contamination, and is known to bacteriologists by the name of 

 B. coli communis. This is a type of Bacillus found living in 

 the intestines of animals, and is not found in any abundance 

 in nature, outside of the intestines. When, therefore, any 

 water is found to contain this organism in any quantity, it is 

 a fairly safe indication that the water is contaminated with 

 sewage. If bacteriologists, in their study of drinking water, 

 discover the presence of this organism they conclude that the 

 water is contaminated with sewage and, hence, unsafe to 

 drink; not because B. coli is in itself dangerous, but because 

 it indicates sewage contamination. 



What about the presence of this organism in milk? 



In the first place, if the presence of B. coli in milk should 

 result in its being pronounced unfit for drinking, a large pro- 

 portion of the milk in our markets would be under ban, for, 

 while it is not by any means universal in milk, still it is found 

 with very great frequency. Indeed, it is quite evident that 

 one would naturally find it in milk. Anyone who knows the 

 conditions under which milk is produced, even in the best and 

 most cleanly dairies, will easily recognize that there is always 

 a possibility of the milk being contaminated with animal excreta. 

 This excrement is almost sure to contain B. coli; hence, it will 

 follow that the milk will very likely show its presence from 

 such contamination. It may, therefore, be fairly safe to assume 

 that the presence of this bacillus in milk indicates the con- 

 tamination of the milk with animal faeces; but it by no means 

 follows that this should be sufficient to condemn milk for drink- 

 ing purposes. It is true that water contaminated by sewage 

 is unsafe to drink, because it contains excreta from human 

 bodies and is, therefore, quite likely to contain germs of human 

 diseases, chief among them typhoid fever. Anything con- 



