RABIES. 461 



an incubation period of several weeks, and Pasteur conceived that it 

 would be possible to anticipate the symptoms, which would naturally 

 follow in a dog which had been bitten or inoculated, by giving 

 them a mild form of hydrophobia by the injection of attenuated 

 virus of short incubation period. These experiments showed that 

 it was possible to do this, and the outcome was the introduction of 

 a system of protective inoculation in the human subject. Pasteur 

 succeeded in giving immunity from hydrophobia to about fifty dogs 

 of every age and breed. 



In 1885 Joseph Meister, a boy nine years of age, bitten badly 

 by a mad dog upon the hands, legs, and thighs, was brought to 

 Pasteur. At a post-mortem examination of the dog, its stomach 

 was found full of bits of hay, straw, and wood, and it had been 

 unquestionably rabid. On July 6th, sixty hours after Meister had 

 been bitten, a syringe full of marrow from a rabbit which had died 

 on June 21st, and therefore fifteen days old, was injected beneath 

 the skin over the right hypochondriac region. The next morning 

 Meister was inoculated with a spinal cord fourteen days old, and so 

 on every day, till on the sixteenth a cord only one day old was used. 

 So many injections, however, need not have been given, as it was 

 subsequently found that the spinal marrows injected during the 

 first five days were inert when tested on rabbits. The marrows of 

 the next five days showed an ascending scale of virulency, until, on 

 the last two days of the treatment, Meister had been inoculated 

 with a virus so virulent that it was capable of causing hydrophobia 

 in dogs after ten days' incubation. Meister remained completely 

 free from hydrophobia. From that time to the present day many 

 thousands of patients have been treated in Paris by slightly modified 

 methods, and it is very generally believed that a real prophylactic 

 agent has been discovered. 



Pasteur suggested that the rabic virus might consist of two 

 distinct substances a living virus capable of developing in the 

 nervous system, and a secondary product which, in sufficient pro- 

 portions, might have the property of hindering the development 

 of the living virus. The nature of this living virus is quite 

 unknown. 



According to a return of the inoculations at the Pasteur In- 

 stitute, the total number of persons treated in 1895 was 1,523, of 

 whom five died. In three cases the symptoms of hydrophobia 

 occurred within a fortnight of the last inoculation. If these three 

 cases are omitted, the number of persons treated is reduced to 1,520 

 and the deaths to two. The results are shown in the following table,. 



