Contamination of Milk. 31 



thus indicating that the abundance of bacteria found in 

 the fore milk is due to the flushing out of the lower por- 

 tion of the cistern and duct by the first few streams re- 

 moved. 



Kinds Of bacteria in fore milk. The effect of these or- 

 ganisms on milk will depend upon the character of the 

 same. As a rule the number of the different species found 

 is usually small, a condition due in all probability to the 

 fact that the surroundings in the udder favor a rapid 

 growth of certain forms. According to Boiley 1 the bac- 

 terial flora may vary considerably, although certain types 

 reappear with striking constancy if once found in the 

 udder or teat. What these forms are is a question of con- 

 siderable importance, for it would seem that the numerical 

 predominance of those present in the fore milk might in- 

 fluence the character of the fermentation of the whole 

 milk. 



Harrison 2 claims to have found peptonizing bacteria in 

 the fore milk, while Marshall 3 reports organisms that re- 

 sist pasteurizing. Boiley, in thirty experiments, found 

 twelve out of sixteen species to belong to the lactic class. 

 Boiley and Hall failed to find gas-producing forms in the 

 milk of ten cows that were examined for a period of three 

 months; but the observations of Moore and Ward 4 show 

 that gas-generating and taint-producing species are to be 

 found. This fact is important in the selection of milk 

 from a single animal for the cultivation of a starter. Hast- 

 ings has made the interesting observation in the writer's 

 laboratory, that the fore milk, although much richer in 



i Boiley, Cent. f. Bakt., II Abt,, 1895, 1:795. 



a Harrison, 1. c., p. 108. 



Marshall, Bull. 147, Mich. Expt. Stat., p. 42. 



* Moore and Ward, Bull. 158, Cornell Expt. Stat., Jan., 1899. 



