PRACTICE OF MEDICINE AND HYGIENE 



the case with the inoculated. That means that, 

 if everybody in the United States were vacci- 

 nated against typhoid, instead of there being 

 400,000 cases of typhoid fever during the com- 

 ing year there would be 40,000; and, among 

 these 40,000 cases there would be 400 deaths. 

 At present there are 40,000 deaths, annually 

 among the 400,000 cases. Thus vaccination 

 against typhoid might be looked to to save 

 39,600 lives a year in the United States, and 

 prevent 360,000 persons from having the dis- 

 ease. And this work has only begun. 



The final phase of animal experimentation in 

 connection with typhoid fever, which may be 

 mentioned here, involves an animal which has 

 more to do with the disease than any excepting 

 man. It is the common fly. Dating from the 

 time of the Spanish war, medical men have 

 been studying the relation of the fly to typhoid 

 fever. Thousands of these animals have been 

 sacrificed in these investigations; and the in- 

 dictment against the fly is indefensible. The 

 fly is a notorious seeker after decomposing 

 material, and the infected emanations from a 

 typhoid patient if accessible to the fly are soon 

 alighted upon. Many studies of a fascinating 

 and convincing nature have shown the feet of 



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