DENTIGEROUS CYSTS IN THE TEMPORAL REGION. 5 



The sinuses vary in extent, some being only three quarters to an 

 inch and a half, others three or four inches deep. A probe, when 

 introduced, comes in contact with a rough, irregular, bony surface, 

 which gives a sensation similar to that produced by a fragment of 

 necrosed bone still adherent to the surrounding parts. Sometimes 

 one can distinguish an irregular protuberance, surrounded by a trifling 

 circular depression. In other cases, like that to which I have just 

 drawn your attention, the body encountered is moveable. What- 

 ever its position and characters, the sinus always discharges a thin 

 greyish pus, more or less abundant, inodorous or foetid, which glues 

 together the neighbouring hair, and sometimes forms on the cheek or 

 parotid region a long streak, in which greyish particles may be 

 detected. 



A sinus of this nature being formed, the condition may persist for 

 years without much change ; the amount of suppuration varying from 

 time to time. In some animals the discharge almost ceases at certain 

 periods, and the sinus, becoming reduced to very trifling dimensions, 

 seems to heal. Later the parts become inflamed, suppuration in- 

 creases, and the flstula reopens, or another appears in the neighbour- 

 hood. In old-standing cases several cicatrices, due to closed sinuses, 

 may often be detected around the wound. 



Besides the recorded cases of multiple supernumerary teeth, others 

 exist where several dental cysts have developed in succession, each 

 giving rise to a fistula. 



In Rodet's case, after the extraction of the first tooth a second cyst 

 appeared. The fourteenth case treated by Macorps was operated on 

 twice at an interval of three months. Each time a tooth was 

 removed. A little later a new fluctuating swelling appeared, due to 

 the eruption of a third tooth. Such relapses, however, have only been 

 recorded in a few instances. 



As a rule these cysts neither produce functional disturbance nor 

 general symptoms, though exceptions to this rule exist. Two patients 

 treated by Macorps and Gamgee showed difficulty in mastication 

 and general wasting, troubles which only disappeared after removal 

 of the tooth. Much graver complications may occur when the tooth 

 develops within the cranial cavity, thrusts back the dura mater, and 

 compresses the brain. Bay has related an interesting case of this 

 ciiaracter. A horse which had long suffered from a non-fistulous 

 swelling of the temporal region, but without accompanying disturb- 

 ance, died in twenty-four hours with symptoms of meningitis and 

 encephalitis. Autopsy revealed the presence within the cranium of 

 a new growth of apparently osseous nature, which, on more careful 



