37(3 TYPHOID FEVER 



hours. During the next ten days the blood of the individual 

 begins to manifest, when tested, an agglutination reaction, and 

 further, Wright has found that usually after the injection there 

 is a marked increase in the capacity of the blood serum to kill 

 the typhoid bacillus in vitro. The second injection usually 

 produces practically no symptoms, but ought to be followed by 

 a further rise in agglutinins in the serum. These observations, 

 there is little doubt, indicate that the vaccinated person possesses 

 a degree of immunity against the bacillus, a conclusion borne 

 out by the results obtained in the use of the' vaccine as a 

 'prophylactic against typhoid fever. Extensive observations 

 were made in the British army in India, and in the South 

 African War the efficacy of the treatment was put to test. 

 Though in isolated cases not much difference is observed among 

 those treated as compared with those untreated, yet the broad 

 general result is that on the one hand protective inoculation 

 diminishes the tendency for the individual to contract typhoid 

 fever, and, on the other, if the disease be contracted, the likeli- 

 hood of its having a fatal result is diminished. Thus, in India, 

 of 4502 soldiers inoculated, '98 per cent, contracted typhoid, 

 while of 25,851 soldiers in the same stations who were not 

 inoculated, 2 '54 per cent, took the disease. In Ladysmith 

 during the siege there were 1705 soldiers inoculated, among 

 whom 2 per cent, of cases occurred, and 10,529 uninoculated, 

 among whom 14 per cent, suffered from typhoid. Wright 

 collected statistics dealing in all with 49,600 individuals, of 

 whom 8600 were inoculated, and showed a case incidence of 

 2 - 25 per cent., with a case mortality of 12 per cent. ; in the 

 remaining 41,000 uninoculated the case incidence was 5 - 75 per 

 cent, and the case mortality 21 per cent. The best results 

 are obtained when ten days after the first inoculation, as recom- 

 mended above, a second similar inoculation is practised. 

 Wright found that in certain cases immediately after inoculation 

 there was a fall in the bactericidal power of the blood (negative 

 phase), and he is of opinion that this indicates a temporary 

 increased susceptibility to the disease. He therefore recommends 

 that when possible the vaccination should be carried out some 

 time previous to the exposure to infection. The deductions 

 originally made have been amply confirmed during the present 

 war, and the method has been extended by using a vaccine which 

 protects not only against typhoid fever but also against the 

 paratyphoid infections (v. infra). 



Vaccine Treatment of Typhoid Fever. — As in the case of 

 other acute infections, vaccines have been used in the treat- 



