Remarks on Vaccination against Typhoid Fever

MR. HAFFKINE suggested rather more than twelve months ago to one of us that the method of vaccination which has proved so effectual in combating cholera epidemics in India might, mutatis mutandis, be applied also to the prophylaxis of typhoid fever.Since that ime, this question has been constantly engaging our attention, and we have gradually elaborated the method of antityphoid vaceination, which is to be briefly described in this paper.Our first vaccinations against typhoid were undertaken in the months of July and August of lost year.These vaccina- tions were put on record by one of us in the Lancet on September Igth,1896, in a paper which dealt primarily with the question of serous hwemorrhage.A reprint of this paper was sent among others to Professor Pfeiffer.Nearly two months after the date of this paper ProfessorPfeiffer" published, in conjunction with Dr. Kolle, a paper on Two Cases of Typhoid Vaccination.The method pf inocula- tion which these authors have adopted, is exactly similar to the one that we had previously adopted.Like our own method it was based upon the methodf s which have been sosuccessiully employed by Mr. Haffkine in his anticholera in- oculations.After this historical discursus, we may without further prologue proceed to consider, first, the general principles upon which these typhoid vaccinations are based; secondly, the methods which are adopted in preparing the vaccines; thirdly, the dosage and thestrength of the vaccines; fourthly, the clinical symptoms which supervene upon the inoculation of those vaccipes; fifthly, the method of gauging the effect of these vaccinations ; lastly, we shall consider certain questions with reference to the probable duration of the immunity and in connection with the application of these vaccines.PRINCIPLES UPON WHICH THE PROPOSED METHODOF TYPHOID VACCINATION IS BASED.The object ofall vaccination processes is, first, to achieve