ACTINOMYCOSIS OP THE JAW. 353 



the alveolus of the tooth (epulis), and are much less easy to deal with. 

 It is important to note from what point the tumour arises and whether 

 swelling of the submaxillary glands already exists. Tumours of 



Fig. 329. — Botryomycosis of the lower jaw. 



the jaw of epithelial type are probably due in most instances to 

 paradental epithelial debris, thus resembling the dentigerous and 

 dermoid cysts. 



(8.) ACTINOMYCOSIS OF THE MAXILLA. 



Actinomycosis of the maxillae occurs in all domesticated animals, 

 and has even been seen in elephants, though the ox is by far the 

 most frequent sufferer. Imminger found the disease localised in the 

 jaw in 14 out of 15 cases of actinomycosis. Marey records 541 cases ; 

 117 of these affected the bones of the skull. The changes produced 

 by the actinomyces resemble those due to tumour growth, and have 

 frequently been mistaken for the latter. Vachetta describes the 

 growths as osteosarcomata. All the older reported cases of " sar- 

 coma " of the maxilla are probably attributable to actinomycosis. 



Infection with actinomyces following injuries to the gums often 

 causes osteomyelitis and rarefying ostitis of the jaw. This generally 

 attacks the lower jaw, but sometimes the upper in addition, and is 

 frequently seen in ruminants, particularly in cattle, but also in goats. 

 The disease usually arises from one or other pre-molar. Pilz saw a 

 tumour of this kind in a horse : it had developed in the neighbour- 

 hood of the first and second lower molars, and had four fistulous 

 openings, from which a yellowish pus was discharged. 



