DISEASE GERMS IN MILK. l6l 



strange that these products, containing as they do, bacteria reckoned 

 by the hundreds of millions per c.c., should be recommended as 

 beverages for infants and invalids. A glassful of well soured 

 milk will certainly contain 100,000,000,000 bacteria, and yet it 

 is a wholesome as well as a refreshing beverage. The explanation 

 however, is simple enough. These myriads of bacteria are practically 

 all of the type of lactic acid bacteria, which are not only harmless 

 in themselves, but which prevent the growth of various kinds 

 of putrefactive germs that might produce trouble in the intestine. 

 The presence of a goodly number of lactic acid bacteria, therefore, 

 may prevent the growth of certain types of intestinal putrefaction 

 that would otherwise cause trouble. The farmer's belief that 

 butter-milk and sour milk are healthful drinks, which seemed hardly 

 credible for a while when the immense numbers of bacteria contained 

 in them were first recognized, appears, after all, to be well founded 

 on scientific fact. The use of such milk is becoming recommended 

 very widely, and already there are on the market commercial prepa- 

 rations of lactic bacteria to be used in preparing such milks. These 

 preparations, as a rule, contain the particular form of lactic bacteria 

 mentioned on page 148 which has the characteristic of being more 

 vigorous, and making milk more acid than the ordinary lactic acid 

 bacteria, and, therefore, having in even greater degree this power of 

 preventing the growth of other more mischievous organisms. The 

 healthful properties ascribed to the alcoholic beverages mentioned 

 on page 158 are probably due to the presence of the beneficent 

 lactic acid bacteria. 



DISEASE GERMS IN MILK. 



It has long been recognized that milk may be a distributer of 

 disease. This general statement is disquieting, but the knowledge 

 is of little use unless it can be made more definite. The subject 

 can be made more intelligible if we notice what kind of diseases 

 are thus distributed and how the dangers arise. There are four defi- 

 nite diseases known to be distributed in this way, and, in addition, 

 a less definite type of intestinal trouble. 

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