BACILLUS TYPHOSUS 115 



have been made with success. These attempts take the 

 direction of injecting the bacilli in such a form that they 

 cannot produce the disease, but yet set up some resistance 

 to it comparable to that acquired by passing through a 

 spontaneous attack. The bacilli are prepared like the vac- 

 cines or bacterins described on p. 69, and injected under the 

 skin. A slight fever may result, but no further bad effects 

 have been noted. All symptoms are over in twenty-four 

 hours after each injection. The bacteria are introduced 

 three times in quantities of 500,000,000, 1,000,000,000 and 

 1,000,000,000 at ten-day intervals. The immunity resulting 

 is supposed to last about two years. This vaccine method 

 is well adapted for and most used by armies going into 

 camps. The results in our army and that of Great Britain 

 have been very encouraging. It should be taken by nurses 

 doing army nursing or seeing many typhoid cases. 



Colonel Russell, U. S. A., concludes his investigations 

 into the theory and practice of antityphoid vaccination as a 

 prophylactic as follows : 



1. Antityphoid vaccination in healthy persons is a harm- 

 less procedure. 



2. It confers almost absolute immunity against infec- 

 tion. 



3. It is the principal cause of the immunity of our troops 

 against typhoid in the recent Texas maneuvers. 



4. The duration of the immunity is not yet determined, 

 but is assuredly two and one-half years and probably longer. 



5. Only in exceptional instances does its administration 

 cause an appreciable degree of personal discomfort. 



6. It apparently protects against the chronic bacillus 

 carrier and is at present the only means by which a person 

 can be protected against typhoid under all conditions. 



7. All persons whose profession or duty involves contact 

 with the sick should be immunized. 



8. The general vaccination of an entire community is 

 feasible and could be done without interfering with general 



