ACTINOMYCOSIS OF THE JAW. 
103 
membrane, and possessing a narrow base are easily extirpated. They 
must not be mistaken for those new growths which arise from 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 
Fig. 61.—Botliryomycosis of the lower jaw. 
swelling of the submaxillary glands already exists. Tumours of 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 MAXILLxE, 
SPINAVENTOSA. 
Actinomycosis of the maxilbe 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 “sarcoma” of the 
maxilla are probably attributable to actinomycosis. 
Infection with actinomyces following inj uries 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 neighbourhood of the first and 
