210 AGRICULTURAL BACTERIOLOGY. 



cial articles with special names, are to be unhesitatingly con- 

 demned. 



5. The unusual dairy infections, slimy milk, bitter milk, etc., 

 are due to uncommon sources of bacterial contamination and 

 may be prevented by proper cleanliness, and removed by the 

 application of disinfection, just as soon as the dairyman can 

 find out the source from which the contaminating bacteria 

 find entrance into the milk. 



PATHOGENIC BACTERIA IN MILK. 



Most of this immense number of bacteria are perfectly harm- 

 less to human health. The presence of lactic bacteria, which 

 form the vast majority in milk that has become a few hours 

 old, is perfectly consistent with the wholesomeness of the 

 milk. Indeed there are some reasons for believing that lactic 

 bacteria are of direct advantage to the human stomach and 

 intestine, aiding in the proper control of digestive processes. 

 At all events they do not appear to be harmful and, except for 

 the fact that they produce a souring, the lactic bacteria are 

 desirable rather than undesirable inhabitants of milk. Their 

 presence commonly prevents the growth of other bacteria 

 which would be more harmful, even pathogenic bacteria being 

 sometimes prevented from growing by the development of 

 the lactic organisms, 



But other bacteria are sometimes present in milk, which are 

 of a very decided injury to the consumer. The possibility of 

 disease bacteria getting into milk and by this means being 

 carried to the consumer, has long been recognized. That this 

 is possible is evident, but to what extent it is an actual occur- 

 rence is not yet fully settled. A large amount of evidence 

 has been accumulating on this matter in recent years and some 

 very definite facts are known. The number of diseases which 

 are distributed by milk is not large and is chiefly confined to 

 the following: 



