3. REPETITION AND IMITATION. 301 



The contagion from the bite of a mad dog dif- 

 fers from other contagious materials, from its being 

 communicable from other animals to mankind, and 

 from many animals to each other ; the phenomena 

 attending the hydrophobia are in fame degree expli- 

 cable on the foregoing theory. The infectious mat- 

 ter does not appear to enter the circulation, as it can- 

 not be traced along the courfe of the lymphatics from 

 the wound, nor is there any fwelling of the lympha- 

 tic glands, nor does any fever attend, as occurs in 

 the fmall-pox, and in many other contagious difeafes ; 

 yet by fome unknown procefs the difeafe is commu- 

 nicated from the wound to the throat, and that 

 many months after the injury, fo as to produce pain 

 and hydrophobia, with a fecretion of infectious fali- 

 va of the fame kind, as that of the mad dog, which 

 inflicted the wound. 



This fubject is very intricate. It would appear, 

 that by certain morbid actions of the falivary glands 

 of the mad dog, a peculiar kind of faliva is produced; 

 which beirig inftilled into a wound of another ani- 

 mal, ftimulates the cutaneous or mucous glands into 

 morbid actions, but which are ineffectual in refpect 

 to the production of a fimilar contagious material ; 

 but the falivary glands by irritative fympathy are 

 thrown into fimilar action, and produce an infectious 

 faliva fimilar to that inftilled into the wound. 



Though in many contagious fevers a material 

 fimilar to that which produced the difeafe, is thus 

 generated by imitation ; yet there are other infectious 

 materials, which do not thus propagate themfelves, 

 but which feem to act like flow poiibns. Of this 

 kind was the contagious matter, which produced the 

 jail-fever at the afllzes at Oxford about a century 

 ago. Which, though fatal to many, was not com- 

 municated to their nurfes or attendants. In thefe 

 cafes, the imitations of the fine veflels as above def- 

 cribed, appear to be imperfect, and do not therefore 



X 2 produce 



