On Rabies. 



61 



parasitical, lung disease, or other ailments, such as diarrhoea, and an 

 epizootic form of nasal catarrh, invariably and rapidly fatal, to which 

 rabbits in confinement seem to be very liable. 



For the sake of uniformity I have latterly always used in these 

 intracranial inoculations 0*1 c.c., or one minim and a half of the 

 mashed medulla. 



Another experiment was as follows :— Two dogs were inoculated, 

 18/9/86, from the medulla of a rabbit of short incubation period. 

 The one a rough terrier, D 8, intracranially by trephining, the other 

 a smooth terrier, D 9, by injecting half a c.c. of mashed medulla 

 into the tibial vein. 



Two rabbits were inoculated intracranially from the same cord; 

 they both died infected, with typical symptoms and appearances, after 

 an incubation period of seven days. 



Both the dogs, however, D 8 and D 9, remained unaffected. The 

 one, D 8, after the lapse of four months was then bitten sharply by 

 a rabid dog in several places on the fore-leg, which had been previously 

 shaved; but again in upwards of two months more has shown no 

 symptoms of infection, though some rabbits bitten by the same dog 

 were infected and died in the usual manner. The other dog, D 9, 

 after the lapse of some months was again injected in the tibial vein 

 with half a syringeful of virulent rabbit's medulla, but it also up to 

 the present time (five months after inoculation) has shown no dis- 

 turbance, though two rabbits inoculated intracranially from the same 

 virus died infected in the usual course. 



This result was quite unexpected, both from my own experiments 

 with rabbits and from the statements of others ; it shows how very 

 much more strongly refractory to the infection with the virus of 

 rabbit rabies dogs are than are rabbits themselves, in which, by 

 intracranial inoculation, infection is produced almost invariably. 



All immunity from, or refractoriness to, infection is relative, as in 

 the original case of vaccination against variola, and also in rabies, as 

 shown conclusively long ago by Hertwig (loc. cit., infra), also by 

 Cbauveau in the refractoriness of Algerian sheep to anthrax 

 (' Comptes Eendus,' vol. 90, 1880, p. 1525), and stated in express terms 

 by Pasteur himself in reference to the general theory of protection, 

 (ibid., vol. 90, 1880, p. 953). Its bearing upon testing the results of 

 inoculation in dogs, with the object of prophylaxis, is referred to 

 below. 



To examine the infectivity of the peripheral nerves, I took a portion 

 of the sciatic nerve of a rabbit recently dead, one of a series of six or 

 seven days' incubation period, and triturated it with bouillon in the 

 usual manner, but as it was more viscid or tenacious than the medul- 

 lary substance, I was obliged to dilute it more than in the usual pro- 

 portion, in order to. render it sufficiently fluid to inject. 



