480 Chapter XV 



on this subject is marked by its great exactness, as it is easy to apply 

 to animals the most rigorous experimental method. In the case of 

 the human subject this is not such an easy matter. As it is impossible 

 to submit him to experimental proof we are obliged to be satisfied 

 with observation, controlled by statistical data. The experience of 

 more than 100 years has, however, been sufficient to demonstrate the 

 great utility of vaccinations against small-pox with the virus of cow- 

 pox which is innocuous for the human subject. In the case of antirabic 

 vaccinations we have to deal with injections into the human subject, 

 first of weakened viruses and then of virulent viruses. Here, how- 

 ever, it is a question of the preservation of the already infected human 

 organism, which, very often, only comes under treatment during the 

 incubation stage of rabies. One can readily understand the hesitation 

 to inoculate even weakened viruses into the human subject, especially 

 [503] when we are not dealing with altogether exceptional cases such as 

 Ave have in the protection against rabies. We have, therefore, but few 

 examples in which the methods of vaccination by micro-organisms 

 have been applied to man. Such injections were first tried by Ferran^ 

 against Asiatic cholera. Having succeeded in vaccinating guinea-pigs 

 against experimental cholera septicaemia, the Spanish investigator 

 attempted to inoculate cholera vibrios into the subcutaneous tissue of 

 man, hoping thus to vaccinate him against true cholera. In this way 

 he was able to demonstrate that the subcutaneous injection of living 

 vibrios never sets up symptoms of cholera. The injection is followed 

 by a general reaction in the form of fever, pains in the back and 

 inflammation at the point of inoculation, in a word, transient phenomena 

 of little gravity. Encouraged by these initial results Ferran, profiting 

 by the outbreak of cholera in the province of Valentia, injected into 

 more than 20,000 persons living cultures of Koch's vibrio. The results 

 published by him did not, however, furnish any real proof of the 

 possibility of conferring immunity against intestinal cholera by means 

 of subcutaneous injections. Later Hafi'kine^ modified Ferran's primi- 

 tive method somewhat, and instead of living vibrios he injected 

 vibrionic cultures killed by heat or by antiseptics. During the cholera 

 epidemic of 1892 and 1893 he tried the inoculation of these killed 

 vibrios into man, with the object of vaccinating against Asiatic 



^ " L'inoculation preventive centre le cholera morbus asiatique" (translated from 

 the Spanish), Paris, 1893. 



2 "Anti-cholera Inoculations in India," Indian Med. Gaz., Calcutta, li>95, J^o. 1. 

 [Also Report to the Guv. of India, Calcutta, 1895.] 



