NEUROMATOUS TUMOURS. 433 



of the cut nerve. They sometimes cause great pain, manifested 

 more particularly when the horse is standing still. He will 

 then often lift his foot from the ground, as if the pain were 

 lancinating; but the lameness is not so evident when he is 

 made to move. When the tumour is pressed upon, or handled 

 in any way, the patient evinces acute agony. Sometimes, how- 

 ever, these tumours, although of some magnitude, cause no in- 

 convenience ; but they are apt to be struck by the opposite foot, 

 and so cause the animal almost to fall to the ground. They 

 sometimes make their appearance in a short time after the 

 operation of neurotomy, and are the result of a badly performed 

 operation; the operator having divided the nerve below the 

 upper angle of the wound in the skin, thus leaving a portion 

 of it in the wound, which, becoming embraced in the reparative 

 material, forms a nucleus for the growth of the neuroma. 

 The only treatment is excision by the knife. 



V. — CARTILAGINOUS TUMOURS, OR ENCHONDROMATA. 



These may take place in the soft parts, or in bone; their 

 favourite seat being the region of the sternum, or upon the ribs. 

 They are frequently caused by external injury. There are two 

 forms of them; one being round or oval, with well-defined 

 borders, and the other having no well-defined limits, but resem- 

 bling an infiltration into the surrounding structures. In the 

 latter case it will generally be found that the tumour arises from 

 the development and growth of cartilage in an inflammatory 

 exudate ; and wounds involving the sternum are very apt to be 

 accompanied by this complication. 



To the touch these tumours are hard and dense, but present 

 a slight elasticity. They gradually increase in size, and when 

 on the sternum become a source of hindrance to the animal's 

 movements, causing him to move with the fore legs wide apart, 

 and with apparent stiffness in the gait. The skin over the en- 

 largement soon becomes raw by the friction of the elbow on its 

 surface. 



The rounded form of tumour generally appears on the carini- 

 form cartilage as a globular enlargement, hard and firm to the 

 touch, causing little or no inconvenience to the animal, unless 

 interfered with by the collar. 



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