THROMBUS PHLEBITIS. 431 



externally, and a very considerable tumour may thus form. 

 This is a thrombus. Having carefully pinned the outer 

 opening, the animal's head must be held up to favour the 

 regular flow of blood through the jugular, and cold water 

 may be freely poured over the part at intervals, without pres- 

 sure, and without disturbing the pin. Thrombus is most apt 

 to occur in bleeding horses from the brachial vein. Fortu- 

 nately, now-a-days, we do not have recourse to bleeding to the 

 extent it was formerly practised, and we see fewer cases of 

 thrombus than in days gone by. The result of thrombus is 

 often inflammation of the vein. 



PHLEBITIS. 



The result of wounds in veins, especially by rusty instru- 

 ments, is not unfrequently inflammation. Phlebitis may, 

 however, occur independently of injury, as an idiopathic 

 affection, but this is extremely rare in the lower animals, and 

 I shall consider it when I refer to pycemia, or purulent fever, 

 in a future chapter. Traumatic phlebitis for such is the 

 name to apply to inflammation of a vein due to injury of the 

 latter occasionally occurs without a very readily discovered 

 cause, and though sometimes a dirty instrument may have 

 been used, practitioners have met with it when they have 

 been extremely careful in the operation. A not unfrequent 

 cause is the animal rubbing its neck after bleeding, and for 

 this reason the head should be tied up for a number of hours 

 as a rule. The production of a thrombus as the result of 

 bleeding is to favour the development of phlebitis. 



Symptoms of Phlebitis. The wound which has been 

 inflicted in blood-letting becomes surrounded by a swelling 

 of a hot and painful character; an ichorous discharge oozes 

 from beneath the tow or hair used to twist round the pin, and 

 not unfrequently there is considerable constitutional irritation, 



