To those not wholly familiar with the subject it will come as a surprise to know that the theory of immunization by bacterial vaccination is nearly as old as the science of bacteriology itself, dating from Pasteur's experiments with the anthrax bacillus in the early eighties of the last century.
It is now twenty-five years since Frankel and Simonds immunized rabbits against typhoid, and fifteen years since Pfeiffer and Kolle and Wright almost simultaneously gave the first typhoid inoculations to man. Partly on account of faulty methods of preparation of the vaccine, and partly on account of false premises and prejudice, typhoid inoculation made little headway and, for a time after the South African war, was somewhat discredited.
With the past five years, however, the practice has been put on a sound footing, first as a prophylactic measure and more recently in treatment, and it is proving its worth in