142 PASTEUR AND HYDROPHOBIA III 



the dog so treated escaped the effect of the poison 

 altogether. 



A very interesting and important result is that in 

 the cases in which the largest amount of poison was 

 used, and the quickest development of the disease 

 followed, the form which the disease took was that of 

 paralytic or "dumb rabies," in which the animal 

 neither barks nor bites ; whilst with the smaller dose 

 of poison and longer incubation period " furious rabies " 

 was developed. Moreover, by directly inoculating on 

 the surface of the brain and spinal cord, Pasteur has 

 been led to the conclusion that the nature of the attack 

 can be varied by the part of the central nervous 

 system which is selected as the seat of inocula- 

 tion. 



Certain theories which have been held as to the 

 mode in which inoculation with the attenuated virus 

 of such diseases as small-pox and anthrax acts, so as 

 to protect an animal from the effect of subsequent 

 exposure to the full strength of the poison, might lead 

 us to expect that the dogs which were inoculated by 

 M. Pasteur with a quantity of rabid virus just small 

 enough to fail in producing the symptoms of rabies 

 would be "protected" by that treatment from the 

 injurious effects of subsequent inoculation with a full 

 dose. This, however, Pasteur found was not the case. 

 Such dogs, when subsequently inoculated with a full 

 dose, developed rabies in the usual way. 



When the virus of rabies is introduced from a dog 

 into a rabbit, and is cultivated through a series of 

 rabbits by inoculating the brain with a piece of the 



