DISEASES OF THE A'EIiVOUS SYSTEM. 163 



might be given, all proving that there exists and can be produced different 

 Mnds of rabies all more or less violent and fatal. 



Guinea pigs soon attain a maximum of virulence; the incubative period 

 is shortened, and by transmission we obtain a virus which surpasses in 

 virulence that of rabies ordinarily met with. 



Jenner propounded the theory that poison called "grease " in the horse, 

 now described more correctly as the horse-pox may be weakened in activ- 

 ity by transmission through cows. This idea of Jenner's struck us as 

 being capable of imitation. Could we attenuate the virus by passing it 

 through the bodies of certain animals? Many attempts were made, until 

 in the case of monkeys, a medium was found. 



December 6, 1883, the bulb of a dog which had been bitten by a child who 

 died of hydrophobia, was taken and a monkey inoculated by trephining. 

 In eleven days the monkey became rabid. From this monkey, the virus 

 was transmitted to a second. In eleven days the second showed signs of 

 rabies. A third monkey became rabid in twenty -three days. Other mon- 

 keys were experimented on. With the bulb of each of these monkeys two 

 rabbits were inoculated by the method of trephining. The rabbits infected 

 by the first monkey became rabid on the thirteenth and sixteenth days; 

 the two from the second monkey on the fourteenth and twentieth days; 

 the two from the third monkey on the twenty-sixth and thirtieth days; 

 two from a fourth monkey on the twenty-eighth day in each case; two 

 from a fifth monkey on the twenty-seventh day in each case ; two from a 

 sixth monkey on the thirtieth day in each case. 



By transmission from monkey to monkey, and from monkey to rabbits, 

 the strength of the poison seemed weakened. A dog inoculated with the 

 bulb of the fifth monkey had incubation period of not less than fifty-eight 

 days; other experiments confirmed these results. We thus found out a 

 method of attenuating the virus, and a method of vaccinating dogs as 

 prevention against rabies. 



As a starting point we take one of the rabbits inoculated from monkeys 

 to such a degree, that hypodermic or Intravenous injection does not cause 

 death. The preventive inoculations are done with the bulbs of rabbits 

 which have been successfully infected from monkeys to rabbits. Jenner's 

 methods met with opposition. Remembering this I determined to lay my 

 results before a scientific commission. M. Tallieres, Minister of Instruction 

 in France, supported my project. M. Beclard, P. Bert, Bonley, Tisseraud, 

 Yillemin, and Vulpian were appointed to examine my statements and 

 check the facts I had communicated to the Academy of Sciences May 29, 

 1884. M. Bouley was chosen President, and Villemin, Secretary. The com- 

 mittee have recently presented their report to the Minister. I am now able 

 to give a brief account of the flrst report. 



