76 PASTEUR AND AFTER PASTEUR 



weeks before the disease flared up in the rabbit, or 

 it might be some months : or the disease might 

 wholly fail to flare up. Neither inoculation with 

 saliva, nor inoculation with blood, led him to any 

 discovery. ./Then, came the next stage of his 

 work. He adopted the theory, that rabies must 

 be studied, not in the saliva or the blood, but in 

 the brain and the spinal cord : that the disease 

 must be regarded as a poison taking up its chief 

 abode in the brain and the cord^ especially in that 

 citadel of life, the medulla oblongata, the " bulb," 

 the part of the cord which is nearest to the brain. 

 By a strictly aseptic method of experimenting, he 

 succeeded, where Galtier had failed,! in producing 

 the disease, in dogs and rabbits, by putting under 

 the skin a measured quantity of the medulla of a 

 dog dead of the disease. This method, he found 

 was surer to give a positive result than the use of 

 saliva. Still, he had to meet two difficulties ; he 

 had to shorten up the latent period, and he had to 

 make certain of obtaining a positive result in every 

 case without exception. Then came the turning- 

 point of his work. ,He put the dose of medulla 

 not under the skin, but on the surface of the brain, 

 under the dura mater, the membrane which encloses 

 the brain : that is to say, he put the disease where 

 it was most sure of rapid development. The animals 

 were chloroformed ; a little disc of bone was removed 



