76 THE MILK QUESTION 



better to send an inspector up the river and use the routine bac- 

 teriological tests as a check upon his work. 



Fortunately bacterial counts are comparatively easy to 

 make, so that an unskilled assistant may soon be taught 

 to count the number of bacteria in milk sufficiently accu- 

 rately for practical purposes. 



Progressive dairymen find it a distinct advantage to make 

 bacterial coimts of their milk in order to improve the sup- 

 ply. Such counts are of invaluable assistance in controlling 

 methods, in discovering just which cow, what person, or 

 what part of the industry is at fault. 



One of the special advantages accruing from the bacte- 

 riological control at the dairy is that it affords an opportun- 

 ity to exclude the milk of diseased cows. Cows suffering 

 with inflammation of the > udder known as garget, or mam- 

 mitis, which is the most common of all bovine diseases, 

 usually yield a milk rich in bacteria. The milk from an 

 inflamed udder not only contains many bacteria, but con- 

 tains large numbers of the pus-producing organisms, espe- 

 cially streptococci. These streptococci are sometimes par- 

 ticularly virulent and good dairy methods require every 

 precaution to keep them out of the milk. Such milk may 

 be particularly dangerous when fed to infants. 



Finally, bacterial counts are indispensable checks upon 

 the efficiency of pasteurization. 



The number of bacteria in milk is always stated in round 

 numbers. These numbers represent minimal rather than 

 maximal counts; that is, the number of bacteria as given 

 by the bacteriologist is always less than the actual number 

 of bacteria present in the milk. There is no known method 

 by which the entire bacterial population in milk may be 

 counted, because some of them do not grow upon our 

 ordinary culture media; furthermore, a colony is taken to 

 represent a single germ, whereas it may have developed 

 from a cluster. 



The number of bacteria in milk, then, is an index of 



