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SCIENCE 



[N. S. Vol. XLIV. No. 1126 



vince the thinking world that preventive 

 inoculation against typhoid fever is harm- 

 less and that to a striking extent it does 

 protect. The results attained in the Ger- 

 man and English armies and among the 

 personnel of hospitals have assured us that 

 these classes of people, who are the most 

 exposed to typhoid fever, become, when 

 vaccinated, only one half to one sixth as 

 liable to contract the disease as the un- 

 treated. The protection, then, under these 

 unfavorable conditions, is not absolute, but 

 very evident. Much better results have been 

 obtained in the last few years in the United 

 States army, where, in spite of objection, 

 typhoid vaccination has been made compul- 

 sory since 1910 for all men under forty-five 

 years of age. Whereas in the preceding 

 nine years there were on the average 351 

 cases of typhoid annually, since compulsory 

 vaccination the cases have sharply dimin- 

 ished until in 1913 and 1914 there were only 

 four and seven cases, respectively, a truly 

 remarkable showing. These last results 

 have been enough to convince the most 

 skeptical, and have led to widespread adop- 

 tion of the method, not only in armies, but 

 in civil communities. These results in our 

 army, life-saving, convincing and valuable 

 as they have been, are open to a very slight 

 objection in my opinion; they have led the 

 public, and particularly the medical pro- 

 fession, to a slight over-confidence in the 

 efficacy of the method itself. These army 

 results are essentially perfect, at least far 

 nearer perfection than has ever been 

 reached by any similar type of biological 

 preventive or curative treatment, a fact 

 which leads us to suspect that they are ex- 

 ceptional and due to the operation of a set 

 of conditions which, in spite of their exist- 

 ence over a considerable period of time, are 

 not to be counted on. 



Among the conditions that have oper- 

 ated in making these conditions more per- 



fect is the vaccine employed and the method 

 used in its administration. Army officials 

 are, in my opinion, inclined to attribute an 

 undue importance to this factor. They use 

 a certain strain or race of the typhoid bacil- 

 lus derived from England, to which they 

 are inclined to attribute particular prop- 

 erties of immunization. Results elsewhere 

 have indicated, and we believe we have 

 strong evidence from unpublished work in 

 our own laboratory, to prove that a vaccine 

 compounded of a number of strains of the 

 organism is better. The army has intro- 

 duced three instead of the two injections 

 which were formerly used in England, and 

 this is an undoubted advance. 



The fact remains, however, that the army 

 vaccine, or at least vaccines prepared by 

 commercial firms from the army bacillus 

 under identical and simple conditions, do 

 not invariably protect in civil life. Recent 

 reports from the continental armies, each 

 employing a different method, show that 

 in none of them is the protection afforded 

 nearly absolute, in spite of the fact that in 

 parts of the French army four or five in- 

 jections have been given. I am inclined to 

 believe with Sawyer that the superior re- 

 sults in our army are largely due to the 

 fact that the entire body of men has been 

 protected, that there has been no single 

 unprotected spot for an epidemic to get a 

 start and gain in violence, to use a vague 

 and perhaps not wholly accurate simile. 

 Some recent results in Prance certainly in- 

 dicate that antityphoid vaccination is more 

 effective in those groups with the higher 

 percentages of assuredly vaccinated men. 



I have gone somewhat fully into this dis- 

 cussion of the army typhoid vaccine for the 

 purpose of indicating that their results, 

 although exceptional, have by no means 

 convinced other authorities that the meth- 

 ods they employ are in detail the best. Let 

 me emphasize again that we are not now 



