576 BACTERIOLOGY. 



tion in the body as shown by a marked increase in the 

 /agglutinative and bactericidal properties of the blood 

 serum against the particular organism. The favorable 

 results following the use of the Haffkine fluid in pre- 

 venting plague have already been given (see p. 325). 



Wright has introduced a similar method of vaccina- 

 tion against typhoid fever. The prophylactic treatment 

 consists of one or two injections of dead cultures of 

 bacillus typhosus. Caiger ! gives the results obtained 

 in the British regiments serving in India. Amongst 

 15,384 inoculated men the incidence of typhoid fever 

 was 0.8 percent., as against 1.5 per cent, in the uninocti- 

 lated. The case mortality amongst the inoculated was 

 15.6 per cent., as against 26.6 per cent, in the uninocu- 

 lated. The results obtained in the military hospitals in 

 South Africa show that the case mortality was 8.2 per 

 cent, among the inoculated, as against 15.1 per cent, 

 among the uninoculated ; a reduction in the mortality 

 of about 50 per cent. In the staffs of three of the mili- 

 tary hospitals the reduction in the mortality was nearly 

 threefold. 



Bresredka 2 sought to find a method of immunization 

 against plague, cholera, and typhoid that would be free 

 from the objectionable features of the method now in 

 use. For this purpose he places a culture of bacil- 

 lus typhosus into typhoid immune serum until it is 

 completely agglutinated. The bacteria are then removed 

 from the serum by centrifuging and subsequently washed 

 with sterile physiological salt solution in order to 

 remove all trace of the serum. The bacteria are then 

 heated to 60 C. for several hours. When these bac- 



1 Caiger : The Lancet, 1904, vol. ii., p. 1467. 



2 Bresredka : Annals of the Pasteur Institute, 1902, T. 16. 



