ACCIDENTS OF BLOOD-LETTING. 507 



accident, but may be easily recognized by tlie flow of blood wliicli 

 escapes through the nostrils, and possibly by the changes which 

 may affect the respiration by threatenings of strangUng, suffoca- 

 tion, etc. In this serious case the hgation of the blood vessel is 

 the only means of stopping the hemorrhage. 



(b) Wounds of the Caudal Muscles. — This is comparatively a 

 common accident with cattle, but is seldom attended with symp- 

 toms of a serious character. The principal danger consists in the 

 possibility of the formation of fistulous tracts, more or less re- 

 bellious to treatment, as besides the muscles, the tendons, and 

 even the bones may have been injured by the instrument. 



3d — Thkombus, 



This is understood to be a bloody tumor, or hematoma, which is 

 formed around the opening of the veiu by the accumulation of the 

 blood ia the surrounding cellular tissue. It appears when the 

 opening of the vein does not accurately correspond with that of 

 the skin, or when the iucision of the tegument is too small to allow 

 a free flow of the blood through it. It often appears when the 

 animal is allowed to rub himself after the operation, or when the 

 opening of the vein has involved a section of one of the valves. 

 Some veins, as the saphena, the cubital, and the subcutaneous 

 thoracic, are more exposed to thrombus than others, even when 

 the operation has been well performed and completed. At these 

 veins, they are generally not serious, and are readily subdued by 

 simple treatment, if they do not spontaneously disappear. 



But the thrombus, which is sometimes encountered at the jug- 

 ular, is of a more serious character, and is not unfrequently com- 

 plicated with phlebitis. 



The symptoms of this lesion are essentially local, and the 

 symptoms and the disease are, in efiect, one, consisting of a tumor 

 of uncertain, dimensions, according to the quantity of blood col- 

 lected vmder the skin. In the beginning it is roiind, well circum- 

 scribed, soft, and slightly elastic to the touch, but the swelling 

 soon becomes hard, perhaps oedematous, or somewhat diffused, 

 when it has been caused by rubbing on the part of the animal. 



The simplest cases gradually disappear after two or three days. 

 But at other times they are not so tractable, and serious trouble 

 may ensue, the tumor becoming stationary, or perhaps increas- 

 ing in size, and then changing its character. It becomes warm 



