MELANOSIS. 409 



colour. One singular feature in connection with it is, that it 

 never appears except when the animal grows lighter in colour. 

 Melanosis is not to be found in every aged horse of a grey 

 colour ; although I believe melanotic deposits within them to 

 be more common than is generally supposed. 



SxMPTOiis. — The symptoms are of a very simple character. 

 Tumours appear in one or more of the numerous regions of the 

 body, and they may be developed either internally or externally ; 

 if internally, their existence may not be known of or ever 

 suspected, until after the death of the animal, when they may 

 be discovered by an examination of the carcass. 



Externally, melanotic deposits commonly appear in one or 

 other of the following parts, viz. : — around the root of the tail ; 

 in close contact with the anus ; within the mammae; at the sides 

 of the sheath ; in the region of the flanks ; amongst the loose 

 tissues immediately behind the elbow joints ; at the lower part 

 of the trachea in front of the breast ; and upon the sides of 

 the head, in close contact with the parotid glands. 



Internally, they may be found in close contact with the 

 liver ; within the omentum ; amid the duplicate folds of tissue 

 in close contact with the bowels ; amid the lungs ; around the 

 substance of one or both kidneys ; and, in short, of many other 

 localities which it is unnecessary to enumerate. 



Melanotic deposits are always manifested in a very slow 

 insidious manner. At first they may appear as mere specks, 

 which gradually increase to an uncertain size. 



PATHoaNOMO^ic Symptoms and Peoops. — Tlie animal 

 leing grey, and the colour of the hair disapjpearing. The inser- 

 tion of the lancet into the growth ivill at once determine whether 

 its contents are melanotic or not. The colour and consistency of 

 melanotic deposits heing that of printers' ink. 



