VACCINATION 497 



survived the sub-cutaneous inoculation of a small dose of a cholera culture 

 are immune to fatal doses. He therefore applied this method of immuniza- 

 tion to man and has performed more than 50,000 vaccinations. The results 

 show that after two or three sub-cutaneous inoculations of his cultures (which 

 give rise to a slight febrile reaction) the vaccinated individuals are immune 

 against cholera. 



For the preparation of the vaccine Ferran uses a vibrio isolated from 

 cholera stools by the gelatin plate method. The vibrio is grown in broth 

 at 37 C. and for vaccination purposes quantities of 1, 1-5 and 2 c.c. of the 

 culture are inoculated successively at intervals of 5 days. 



The results of Ferran's prophylactic vaccination have been much criticized. 

 At all events he was the first to attempt the vaccination of man against 

 cholera, and the methods advocated since are nothing more than modifications 

 of his procedure. 



Gamaleia suggested the use of cultures killed by heat in place of living 

 organisms. TamanchetT employed cultures killed by carbolic acid. 



II. Haffkine's vaccine. Haffkine considers that to ensure satisfactory 

 vaccination against cholera a fixed virus of increased virulence should be 

 used. 



To immunize guinea-pigs Haffkine inoculates them first with an attenuated 

 strain and afterwards with a strain which has been increased in virulence. 

 He takes a vibrio whose virulence has been raised and fixed by twenty passages 

 through the peritoneal cavities of guinea-pigs and attenuates it by sub- 

 cultivating it several times in broth at 39 C. in a current of air. The cultures 

 thus obtained produce only a local and general reaction on sub-cutaneous 

 inoculation into the guinea-pig. The animal is then inoculated sub-cutaneously 

 with the virus of increased virulence, which is found to cause no disturbance 

 of its health. After this it is immune against all methods of infection with 

 the vibrio (sub-cutaneous and intra-peritoneal inoculation and ingestion). 



This method nevertheless failed to immunize ground-squirrels and suckling 

 rabbits against experimental intestinal cholera (Zabolotny, MetchnikofE). 



To vaccinate man against intestinal cholera, Haffkine proposed inoculating 

 beneath the skin first an attenuated virus and a week later one of his virulent 

 cultures (^th. to T V* n f an &g a r culture). This method was subsequently 

 modified and he now gives a single inoculation of a virulent virus recently 

 recovered from the peritoneum of a guinea-pig. In the case of an adult he 

 injects 0*5 c.c. of an emulsion of an agar culture in about 5 c.c. of sterile 

 water. The results obtained by Haffkine, Powell, Simpson, Wright and others 

 seem very satisfactory. 



III. Kolle's vaccine. For human vaccination, Kolle uses agar cultures 

 made into an emulsion (with sterile normal saline solution) and heated at 

 56 C. for an hour. The inoculation of T \yth to ith of an agar culture sets up a 

 painful inflammation at the site of inoculation which lasts 2 or 3 days. From 

 the fifth day after inoculation the serum of the inoculated individual is endowed 

 with both bactericidal and bacteriolytic properties, and these can still be 

 demonstrated so long as a year afterwards. 



According to Kolle it is a matter of indifference in the case of the guinea-pig 

 whether a virulent or non- virulent vibrio be used. This fact confirms Ferran, 

 who considers that no value attaches to increasing the virulence of the virus 

 by animal passage for the preparation of human vaccines. 



IV. Vaccination with bacterial extracts. The extracts prepared by Schmitz, 

 Turro, Blell (p. 495) are toxic for guinea-pigs : 10-15 mg. is a fatal dose, but 

 if smaller doses (1-5 mg.) be used the animal is immune for several months 

 against both the toxin and the organism. For human vaccination 2 mg. 



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