Infection of Milk. 77 



articles that may be soiled with the same become a posi- 

 tive menace. 



Many different methods of transmitting the contagion 

 exist, such as water, food infected in various ways, 

 contact with infected persons, and through the medium 

 of milk. Milk is not so frequently the cause of dis- 

 semination as the other factors, but where milk sup- 

 plies become contaminated, epidemics of considerable 

 magnitude are wont to occur. The danger from milk 

 is also aggravated by the fact that the typhoid bacillus 

 is capable of withstanding considerable amounts of 

 acid, and consequently finds, even in raw milk contain- 

 ing the normal lactic acid bacteria, conditions favor- 

 able for its growth. In a considerable percentage of 

 cases, the disease is not sufficiently severe to cause the 

 patient to take to his bed. These so-called "walking 

 typhoid" cases are particularly dangerous, because 

 they serve to spread the disease organism more widely. 



A very considerable proportion of the people that 

 recover from typhoid fever still continue to harbor the 

 typhoid bacillus in their urinary and gall bladders. 

 This condition may obtain for years, and since such 

 individuals are in perfect health and are ignorant of 

 their own condition, and since they give off the organ- 

 isms more or less constantly, they are often the cause 

 of extensive milk borne epidemics. Such persons are 

 known as "typhoid carriers" and constitute one of 

 the gravest problems the public official has to contend 

 with in his struggle to prevent the spread of typhoid 

 fever. 



Where outbreaks are caused by milk, they can read- 

 ily be traced by means of the milk route, as there are 

 always a sufficient number of susceptible persons, so 



