674 



INFECTIOUS DISEASES. 



usually slow, and some weeks or months elapse before this stage is 

 reached. 



When the disease attacks the region of the incisors the symptoms 

 are much sooner apparent, and treatment is much easier. The parasitic 

 invasion results from an injury to the jaw caused by shedding of the 

 milk teeth. Swelling of the body of the jaw thrusts the lower lip 

 downwards, interferes with the prehension of food, and calls for 

 prompt treatment. The disease is rarely allowed to attain the degree 

 of development shown in Figs. 269 and 270. 



As in the preceding instance, the animals die of exhaustion unless 

 relieved. 



For reasons difficult to explain, but probably because inoculation 



Fig. 269. — Actinomycosis in the region 

 of the incisors. 



Fig. 270. — Actinomycosis in the 

 region of the incisors. 



is less easy, actinomycosis is much rarer in the upper than in the 

 lower jaw. The disease develops exactly as above described, but 

 shows much less tendency to external ulceration. It invades the 

 maxillary sinus and the region of the palate, and fistulae are found 

 opening into the buccal cavity, while at the same time the region of 

 the forehead is often deformed. 



ACTINOMYCOSIS OF THE TONGUE. 



Actinomycosis attacks the tongue apart from any lesion of the 

 jaws, and produces what is commonly called "wooden tongue." 



The disease develops in the tongue itself, generally in the sub- 

 mucous zone, and causes chronic interstitial inflammation, infiltration 



