88 MODERN DAIRY PRACTICE. 



Increase in Bacterial Content of Milk. The increase 

 of the bacteria in milk depends of course both on the tem- 

 perature and on the kinds appearing in the milk. The 

 influence of the former factor is shown by the following 

 investigations : 



Cnopf and Escherich in Munich found 60,000-100,000 

 bacteria per cc. in a sample of milk recently drawn under 

 precautions of great cleanliness. This milk was kept in a 

 cool cellar at a temperature of 12.5 C. (56.5 F.). After 

 two hours the number of bacteria was 4 times larger than 

 at the beginning, after four hours 8 times larger, after five 

 hours 26 times larger, and after six hours 435 times larger. 

 [Another portion of the same milk was kept at 35 C. in 

 an incubator; the bacteria contained in it had multiplied 



23 times after two hours and 215 times after four hours, 

 1830 times after five hours and 3800 times after six hours. 

 The development of bacteria in milk kept on ice was so 

 small during this time that it could hardly be ascertained, 

 but in the course of some days it reached as high figures as 

 in the other samples.* W.] 



From the laboratory at Riitti the following table is fur- 

 nished concerning the number of bacteria per cc. in 

 milk of Nov. 14, 1889. On the arrival at the laboratory 

 there was found 9300 bacteria per cc. in the milk. 



INCREASE IN BACTERIAL CONTENT. 



When kept at When kept at When kept 

 15 C. 25 C. at 35 C. 



3 hours later 1.06 times 2 times 4 times 



6 hours later 2.5 " 18.5 " 1,290 " 



9 hours later 5.0 107.5 3,794 " 



24 hours later.... 163 62,097. 5,376 



* Centra. /. Bakteriologie, 6, 554. 



