Ill PASTEUR AND HYDROPHOBIA 147 



days, and so on until on the tenth day a cord kept 

 for only one day was used. This was found to cause 

 rabies in a dog not previously treated, and yet had 

 no such effect on the dog subjected to the previous 

 series of inoculations. The dog had been rendered 

 refractory to rabies. In this way M. Pasteur states 

 that he rendered fifty dogs of all ages and races re- 

 fractory to (or " protected against ") rabies without one 

 failure. Virus was inoculated under the skin and 

 even on the surface of the brain after trephining, and 

 rabies was not contracted in a single case. 



Why M. Pasteur makes use of a gradually increas- 

 ing strength of virus, or how he supposes this treat- 

 ment to act so as to give the remarkable result of 

 protection, he has not explained. The experimenter 

 very probably has his own theory on the subject, 

 which guides him in his work ; but whilst he is still 

 experimenting and observing he does not commit him- 

 self to an explanation of the results obtained. We 

 may look in the future for a full consideration of the 

 subject and a definite statement of the evidence at his 

 hands. Meanwhile, it must be remembered that the 

 notes published by M. Pasteur are, as it were, bulle- 

 tins from the field of battle, briefly announcing failures 

 and successes, and are not to be regarded as a history 

 of the campaign or a statement of its scheme and final 

 result. 



Having arrived at this point in his experimental 

 results, M. Pasteur was prepared to venture on to the 

 far more delicate ground of treatment of human beings 

 who had incurred the risk of hydrophobia. 



