Protective vaccinations 481 



cholera. Later he went to Calcutta in order to try his method on a large 

 scale. He was there enabled to inoculate a great number of persons 

 and the statistics which he collected appeared to him to be favourable! 



But studies on the pathogenesis of Asiatic cholera shook the 

 foundations of Ferran's method. The injections of vibrios, living or 

 killed, were found quite capable of vaccinating animals against 

 vibrionic peritonitis and septicaemia, but they appear to exert no 

 influence whatever against poisoning by the cholera toxin. When 

 it had been learnt how to set up true intestinal cholera in young 

 rabbits Ferran's and other similar methods of vaccination were used 

 in vain to prevent the incidence of this disease, which is very similar 

 to Asiatic cholera of man. An experiment^ made at the Pasteur 

 Institute in Paris upon two persons vaccinated by Haffkine, showed [r,04] 

 that they were not protected against the choleriform diarrhoea set 

 up by the ingestion of the cholera vibrios. A third person, who 

 had never been " vaccinated '' and who served as " control," after the 

 ingestion of the same cholera culture, behaved exactly as did the 

 other two. 



From all these data the conclusion was drawn that in order to 

 prevent intestinal cholera it is necessary to use not cultures of 

 vibrios, living or dead, but antitoxic serums. In fact, the majority 

 of young rabbits vaccinated with these serums and afterwards sub- 

 mitted to infection by the cholera virus through the mouth Avere 

 found to be vaccinated against intestinal cholera. It has not been 

 possible, as yet, to apply this method to man, hence we are unable 

 to give a decided opinion. Moreover, as the methods based on 

 Ferran's principle have now been abandoned I have not deemed 

 it necessary to devote a special section to anticholera vaccinations. 

 I could not, however, pass it by in silence, since the attempts to 

 vaccinate man against cholera have led to the trial of a similar 

 method against typhoid fever. 



Pfeifier and Kolle^ were the first to inoculate man with typhoid 

 coccobacilli sterilised by heat. They observed that these injections 

 caused fever, pretty violent pains in the back accompanied by vertigo, 

 shivering and pain at the point of inoculation, without, however, being 

 in any way serious to health. At the same time they found that the 

 blood serum of inoculated persons acquired a very marked protective 

 power (for guinea-pigs injected into the peritoneal cavity with lethal 



1 Ann. de VInst. Pasteur, Paris, 1893, t. vii, p. 579. 



2 Deutsche med. Wchnschr., Leipzig, 1896, S. 735. 



B. 31 



