16 HOUSEHOLD INSECTS 



water supply of the dairy was fairly good. However, 

 we found that the stools of both the wife and husband 

 had been deposited in an open privy vault located 35 feet 

 from the milk-house, which was unscreened and open to 

 flies. The gelatine cultures exposed for 30 minutes in the 

 rear of the privy vault and in the milk-house among the 

 milk-cans gave numerous colonies of typhoid bacilli, as 

 well as colon bacilli and the ordinary germ-life. The 

 source of infection in the dairyman's wife's case is un- 

 known, but I am positive that in all the cases that occurred 

 on this milk route the infection was due to bacilli carried 

 from this vault by flies and deposited upon the milk-cans, 

 separator, and utensils in the milk-house, thereby con- 

 taminating the milk. The dairyman supplied milk to 

 143 customers. Fifty-five cases of typhoid fever occurred 

 and three deaths resulted therefrom." 



THE NATURE OF TYPHOID FEVER AND ITS RELATION TO 



THE HOUSE-FLY 



The relation of the house-fly to typhoid fever is con- 

 sidered the most important phase of the disease-germ- 

 carrying powers of this insect. In order to understand 

 and appreciate this relation clearly, something of the nature 

 of the fever and of the typhoid bacillus should be known. 



Typhoid fever is a so-called enteric disease. That is, 

 it is caused by a bacillus or germ that enters and lives 

 within the intestines of the affected individual, causing 

 ulcerations of these organs. The bacillus affects other 

 organs than the intestines, for example, the spleen, and 

 is often found in the kidneys, liver, lungs, and even in the 

 brain. Its presence, together with a poison that it ex- 



