98 MODERN DAIRY PRACTICE. 



milk seemed, however, to assume a greenish-blue colora- 

 tion. 



Small micrococci appeared in the same milk, and these 

 also produced a distinct alkaline reaction in it. The cult- 

 ures in milk of this bacterium had a disagreeable odor, 

 resembling that of ammonia. A mold, Oidium lactis, was 

 also observed in large numbers in the milk. This is another 

 micro-organism which produces alkaline reaction in the 

 milk. The three latter organisms were by far the more 

 numerous in the sample of milk mentioned. Lactic-acid 

 bacteria were also found, but they had been largely sup- 

 planted. In two calculations of the number of bacteria 

 in one cubic centimeter the ratio of lactic-acid bacteria 

 to bacteria producing the bluish-green color in the milk 

 was about as 1 : 40,000. Unfortunately I was unable to 

 obtain exact data as to this ratio by proper control ex- 

 periments. The micrococcus mentioned was greatly in 

 the minority, both in the cream and in the lower layers of 

 the milk. 



By an analysis of this milk made since the change in 

 the cream -layer spoken of had occurred, I was surprised to 

 find the relation between the different species of bacteria 

 greatly changed, as could readily be seen by the microscope. 

 The micrococci had gained the upper hand in the cream 

 layer, and the bacteria resembling the blue-milk bacillus 

 had been forced to the lower layers of the milk, where they 

 lived a very feeble life, as was proved by later examinations. 

 Being aerobic bacteria, this might be inferred. The lactic- 

 acid bacteria were in a very small minority during the 

 whole experiment, both in the milk itself and in the cream 

 layer. It is plain that the bacteria resembling the blue- 

 milk bacillus produced favorable conditions for the micro- 



