DISEASE GERMS IN MILK IO5 



DETECTION OF DISEASE GERMS IN MILK 



There are within our reach at present no practical means by 

 which we can examine milk and determine whether it contains 

 the germs of any of these four diseases. It is true that proper 

 study will sometimes detect the presence of tubercle bacilli in 

 milk; but the methods are long, complicated and very difficult, 

 and so uncertain that a negative result has no meaning. It 

 would never -be possible by any methods in our possession to- 

 day to make a microscopic examination of milk and guarantee 

 the milk as being free from tubercle bacilli. It is still more im- 

 possible to detect the presence of the other three disease germs. 

 The cause of scarlet fever is not known and cannot, of course, 

 be recognized in milk. The typhoid bacillus very closely re- 

 sembles B. coli, which we have seen is always to be expected 

 in milk, and while the two bacteria can be distinguished from 

 each other, the methods are too long and uncertain to make it 

 possible to apply them in any practical way to the study of 

 milk. The diphtheria bacillus, too, may be detected but only 

 by methods of no practical value in the study of milk. 

 Moreover, no sample of milk is likely to be thrown under sus- 

 picion as distributing disease until long after the particular 

 sample is consumed, when it is too late to make any study. 



It is important to notice that the numbers of bacteria in milk 

 have no relation whatsoever to its chance of distributing these 

 four diseases. Milk that contains as many bacteria as 100,000,- 

 ooo per c.c. is no more likely to contain these germs than milk 

 that contains not more than 10,000, excepting on the general 

 ground that the milk with the higher numbers has been perhaps 

 more carelessly produced. In short, the plans of municipal in- 

 spection which give us facts concerning the bacteria in milk 

 give us not even a hint as to the germs that cause these four 

 diseases. Furthermore, dairy inspection by any means as yet 

 devised is not accurate enough to enable the inspector to de- 



