70 



Mr. G. F. Dowdeswell. 



sequently the only reliable means of preserving them from septic 

 changes is by keeping them under conditions where saprophytes cannot 

 develop, such as that adopted by M. Pasteur and here followed. 

 Another method would be to keep them at a very low temperature. 



The result of attempting to protect rabbits by subcutaneous injec- 

 tions with medullas treated as above, is in accordance with these obser- 

 vations. Here, as recorded below, in the first series of experiments, 

 where large quantities were injected, death shortly followed from 

 sapraemia in every one of the animals inoculated ; in the second series, 

 using smaller quantities for injection, fewer deaths from the same cause 

 occurred, illustrating the distinction between infection with a specific 

 bacterial virus and intoxication by a chemical poison, viz., that in the 

 former case within certain limits, the result is independent of the 

 quantity inoculated, one viable germ producing the same effect as an 

 immeasurably greater number ; but in the other case — the action of a 

 soluble or chemical ferment or poison — the effect is directly and 

 obviously proportionate to the quantity used for inoculation. 



VIII. Protective Inoculation. 



In the first series of experiments upon rabbits, five were taken and 

 inoculated daily after M. Pasteur's original methods with half a 

 Pravaz syringeful — about 0"7 c.c. — of mashed spinal cord, commencing 

 with that dried as just described for 15 days ; on the third day with 

 one of 13 days ; on the fifth with one of 11 days; the sixth with one 

 of 10 ; and so on daily, or as often as a cord of the requisite age was 

 available, till the thirteenth and last inoculation was made with a 

 cord dried one day only, and as several previous experiments had 

 shown, of unmitigated virulence, at least for rabbits. 



Three of the rabbits, however, had died during the course of the 

 inoculations ; one, the youngest of the batch, which died first, appa- 

 rently from accidental causes, the two others from sapraemia ; but two 

 remained for the concluding inoculation, and these both died a few 

 days after it was made. None of them, however, showed any symptoms 

 of infection with rabies, they were those of sapraemia or septic in- 

 toxication. The series of experiments was inconclusive therefore in 

 its results, and it seemed possible that the quantity of matter injected 

 was too large. 



In a subsequent communication (' Comptes Rendus,' 2nd Nov., 

 1886) M. Pasteur, objecting to the results of similar experiments pub- 

 lished by Professor Frisch, of Vienna (' Wiener Med. Wochenschr.,' re- 

 ferred to below), promulgated a new " rapid " or " intensive " method 

 of treatment, which appeared likely to be more successful with rabbits, 

 liable as these animals are to septic poisoning by inoculation with any 

 foreign matter. Accordingly six rabbits were taken, all apparently 



