238 PHYSIC 



animal is in a condition to spread the disease, either by 

 direct inoculation through its teeth and saliva, or indi- 

 rectly, sometimes, in our opinion, by poisoning the food 

 and water used by other animals to which the affected 

 animal has gained access. 



The slowness of the infection, or the prolonged period 

 of incubation, in so many cases, may be explained by the 

 indirectness of the route travelled by the poison when 

 inoculated into distant parts of the body, and where, 

 necessarily, it is somewhat a matter of accident whether 

 it reaches the central nervous system along the nerve ele- 

 ments, or by the more circuitous route of the general 

 lymphatic and blood circulations. 



