TUMOURS. 87 



an old injury, and as the animal got worse, lie was sent to 

 the New Veterinary College on the 3rd of April, 1860. At 

 that time the , horse's condition was very bad. Mastication 

 was evidently impeded, and the animal's muscles wasted. I 

 cast him on the 6th, and passed a probe two inches down- 

 wards and outwards. The discharge was scanty, and a hard 

 circumscribed tumour about the size of a pigeon's egg was 

 situated above the temporal arch. A crucial incision through 

 fche thickened skin and fibrous structures exposed the black 

 top of the tooth substance drawn at Fig. 45. I took a pair 



Fig. 45. 



of bone forceps and tried to extract it, but failed, and with 

 a hammer and chisel easily knocked out of its cavity the 

 larger portion, which had evidently become detached from 

 a small bit readily removed with forceps and scalpel, as it 

 was loosely connected to the walls of a cyst containing the 

 tumour. The whole proved to be made of true tooth 

 substance, and was affected with caries, as shown above. 

 From that day the horse improved, but the fistula never 

 closed perfectly, and during the first week in February last 



