DISEASE GERMS IN MILK 87 



If the simple presence of bacteria in great numbers does not 

 make milk dangerous, it must be that certain kinds of bacteria 

 are harmful, while others are harmless. To understand the 

 relation of milk bacteria to health, therefore, it is necessary 

 to examine more closely the question of the kinds of disease 

 germs liable to be in milk. 1 The accumulated information of 

 the last 20 years has shown us that four specific diseases are 

 commonly thus distributed, together with a fifth type of dis- 

 ease which is less definite. The specific diseases are tuber- 

 culosis, typhoid fever, scarlet fever and diphtheria, and the less 

 definite type includes the diarrheal troubles known commonly 

 by the name of cholera infantum, summer complaint, infantile 

 diarrhea, etc. These are all characterized by diarrheal dis- 

 turbances, but with such varying symptoms that they are not 

 recognized by physicians as sharply defined diseases, and they 

 are moreover produced by more than one kind of a germ. 



DISEASES DIRECT FROM THE COW 



Diseases that come directly from the cow are clearly more 

 difficult to avoid than those which come from external sources. 

 Fortunately, however, the diseases that attack cows do not 

 usually attack man, and, with one exception, are not positively 

 known to be distributed by milk except in the rarest of in- 

 stances. The one disease thus distributed is tuberculosis. 



TUBERCULOSIS 



Extent of Tuberculosis. The very great publicity that has 

 been given in recent years to problems associated with tuber- 

 culosis in cattle renders it unnecessary here to do more than 

 summarize the chief conclusions. It is, to-day, thoroughly 

 recognized that this disease is one of the most serious menaces 



1 Klein. Jour, of Hyg., i., p. 78, 1901. 

 Ernst. The Infectiousness of Milk, Boston, 1895. 

 Lee. Ann. Pub. Health Assn., 1898. 

 Wilckens. Zeit. f. Hyg., xxvii., p. 264, 1898. 



