272 MICROBES AND TOXINS 



with less frequent relapses. The mortality is about four times 

 less among the inoculated than among the non-inoculated. 

 As far as can be judged at present, the effect of the vaccination 

 lasts for about four years. 



There is no necessity to submit a whole family to the dis- 

 comforts of inoculation when one member has taken typhoid ; 

 it is sufficient to isolate the patient and to disinfect strictly 

 the excreta, linen, etc. Vaccination is adapted only for the 

 members of an ambulance and hospital corps during an 

 epidemic, or for troops campaigning in a country where 

 typhoid is raging, and where it is difficult to adopt hygienic 

 measures. 



Plague. — Haffkine's vaccine consists of bacteria killed by 

 heat. The inoculations, especially the first, produce inflamma- 

 tion and pain with a high temperature, the illness lasting for 

 about three days. Two, or even three, inoculations ought to 

 be made. Such vaccinations are suitable in the case of plague, 

 as this disease is a general infection, spreading throughout the 

 blood and organs. In 1 902-1 903 about half a million persons 

 were inoculated in the Punjab, and fairly accurate informa- 

 tion could be gathered regarding a portion of them. On 

 comparison we find : — 



186,797 inoculated, with 3339 cases = i '8 per cent. 



,, 814 deaths = 0'4 per cent. 



639,630 non-inoculated, with 49,433 cases = ^^^ percent. 



II 29,733 deaths = 47 per cent. 



It appears that the inoculation continues to be of benefit for 

 several years after. 



Anti-tuberculous Vaccination. — As far as is known, 

 vaccination against tubercle is possible with living bacilli only, 

 dead bacilli being irleffective, but there is no vaccine as yet 

 which is entirely safe. 



Behring has sought " Jennerian " vaccines, i.e., he has tried 

 to vaccinate one species, cattle, with the virus derived from 

 another species, man. Innumerable experiments have already 

 been made on bovo-vaccination, and they prove at least that 

 a certain degree of immunity may be created towards tuber- 



