Not until the close of the past year, 1912, has it been possible to know how much protection can be obtained from the use of antityphoid vaccine when administered to a large number of men of susceptible age. In the latter part of 1911 the use of antityphoid vaccine was made compulsory for all men in the service under 45 years of age, and as a result we now have records for the year 1912 covering approximately 85,000 vaccinated men. Of these 58,000 were stationed in the United States proper and the remainder in the colonies.
Table 1 shows the typhoid experience of troops in the United States for the past eleven years; the average strength of the home army, the number of cases and deaths are given, and also the morbidity and mortality per thousand of mean strength.
To elucidate this and the following tables the following data are