BACTERIA COMMONLY FOUND IN COWS* MILK. 83 



The examination of the samples taken and kept in 

 this way cannot of course give any information of the 

 number of bacteria in the original fluid, as quantitative 

 bacteriological analyses, as shown in the Introduction, must 

 be made immediately after the sampling. The method 

 used will, however, throw a clear light on the question 

 of the varieties of bacteria found in the different samples. 

 It is possible that some kinds of bacteria may become less 

 active, or even succumb, if the sample is kept too long; 

 but all control analyses which I have made have failed to 

 show any appreciable decrease in the number of the living 

 kinds of bacteria, even after a lapse of three months. A 

 long confinement in the glass tube appears, on the other 

 hand, to cause the destruction of some forms of bacteria, 

 while lactic-acid bacteria have shown strong ability to 

 multiply even after having been kept for fourteen months 

 in the manner described; their ability to develop lactic- 

 acid fermentation in milk was, however, considerably 

 weakened. 



Number of Bacteria in Milk. The number of bacteria 

 in cows' milk depends of course on the treatment to 

 which the milk has been subjected since drawn from 

 the udder. This explains the different data given in the 

 literature on the subject. Cnopf in Munich counted the 

 number of bacteria in recently drawn milk. He found no 

 less than 60,000 to 100,000 bacteria in one cubic centimeter. 

 Freudenreich in Eiitti, Switzerland, on the other hand, 

 found only 9300 per cc. in milk on its arrival in the labora- 

 tory. Jensen in Copenhagen says he is inclined to think 

 that the number of bacteria in the milk cans immediately 

 after all the cows have been milked is many times larger 

 under ordinary Danish conditions than given by Cnopf. 



