VACCINATION AGAINST TYPHOID. 347 



Field Force, in which the efficacy of the treatment was put to 

 test. Though in isolated cases not much difference has been 

 observed among those treated as compared with those untreated, 

 yet the broad general result may be said to leave little doubt 

 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 likelihood 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. In Harrismith, Birt's 

 statistics show that in typhoid occurring in uninoculated persons 

 the mortality was 14.25 per cent, while among 263 inoculated 

 the mortality was 6.8 per cent. Wright has 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 mortaUty of 12 per cent; in the remaining 41,000 un- 

 inoculated the case incidence was 5.75 per cent and the case 

 mortality 21 per cent. The best results seem to be obtained 

 when ten days after the first inoculation a second similar inocu- 

 lation is practised. Wright has found that in certain cases 

 immediately after inoculation there is a fall in the bactericidal 

 power of the blood, 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. 

 There can be very little doubt that in this method an important 

 prophylactic measure has been discovered. 



Anti-typhoid Serum. — Bokenham immunised a horse by filtered bouillon 

 cultures of the typhoid bacillus, and found that the serum had neutralising 

 power for the bacilli when the latter mixed with it were injected into guinea- 

 pigs. When injection of the serum was followed by injection of bacilli, the 

 pathogenic action of the latter was to a certain extent prevented, and there 

 was also evidence of the serum possessing curative properties. 



Methods of Examination. — The methods of microscopic 

 examination, and of isolation of typhoid bacilli from the spleen 

 post mortem, have already been described. They may be iso- 



