BACTERIA IN MILK 211 



by souring. These strange chemical substances 

 so pervert normal digestion that really pathogenic 

 bacteria, the dysentery bacillus group, for example, 

 are able to exert their noxious effects. Streptococci 

 commonly present in the teats, identical with the 

 Streptococcus pyogenes, are said by some to take advan- 

 tage of this disturbed digestion. The examination for 

 streptococci consists in simple staining and finding of 

 them lying in or about pus cells. Health authorities 

 have rules covering this method of examination and 

 the interpretation of results. 



Scarlet Fever, although its cause is unknown, is 

 known to spread along milk routes and has at times 

 been traced to a case on a dairy farm. Foot-and- 

 mouth disease of cattle, another condition of unknown 

 etiology, has been found in children drinking milk 

 from affected cows. The bacillus of diphtheria may 

 live in milk a long time and may be carried along a 

 milk route. It is said that cholera may be transmitted 

 by milk contaminated with polluted water. 



Typhoid Feier. Typhoid fever may be transmitted 

 by milk when a case exists on a dairy farm or a dairy- 

 man uses polluted water to wash his cans. In per- 

 fectly fresh milk the germs do not thrive, although 

 they are not destroyed, but when a little older the 

 milk offers no resistance to their multiplication. If 

 sour, the lactic acid and alcohol not only inhibit their 

 growth, but actually kill them. It is frequently in 

 the period from cooling to distribution and use that 

 contamination occurs. This is done by the hands of 

 dairymen, shippers, tasters (dipping the finger into 

 the milk), or by domestic servants. Carriers of typhoid 



