104 BACTERIOLOGICAL METHODS 



with the intestinal secretions of typhoid patients. The subject 

 of typhoid contamination is therefore intimately associated with 

 the general subject of sewage contamination or contamination 

 with human fecal matter. Very naturally, the typhoid bacillus 

 is far less common than the colon bacillus. In a general way it 

 may be stated that the distribution of the typhoid bacillus is as 

 wide as the distribution of typhoid contaminated sewage. As 

 long as we adhere to the antiquated and highly unsanitary method 





Fig. 30. — B. typhosus from gelatin smear preparation stained with fuchsin (X 



1000). — (MacNeal.) 



of emptying our sewage into the drinking-water supplies just so 

 long will we continue to have epidemics of typhoid fever. Numer- 

 ous statistical records show that the mortality rate from typhoid 

 fever in our larger cities is directly proportional to the filthiness 

 of the drinking-water supply. House-flies are known to be carriers 

 of typhoid and the germs have been isolated from vegetable food 

 materials, from oysters and other shellfish, from milk, etc. 



The laboratory procedure in the examination of foods and 

 liquids for the typhoid bacillus includes the isolation and identi- 



