68 GENERAL THERAPEUTICS FOR VETERINARIANS 



Sometimes a passage for the blood is later opened through the 

 centre of the organized thrombus, or the blood-vessels of the cica- 

 trix become dilated and permit the blood to flow through. 



Artificial Arrest of Hemorrhage. — This aims to close the bleed- 

 ing blood-vessel either by pressure or by aiding coagulation. The 

 most important methods used for this purpose are: 



(a) Ligation of Bleeding Vessels. — The ligature is the only 

 thing which will quickly and surely stop bleeding from the larger 

 arteries and veins. The bleeding vessel is grasped vsith clamp 

 forceps and tied with silk thread. If the vessel cannot be isolated, 

 then the tissue surrounding it is included in the ligature (ligation 

 en masse), a needle being used to carry the thread around through 

 the tissues. When neither of these methods is applicable because 

 of the deep situation of the bleeding vessel, then the ligature must 

 be placed at some accessible point situated centripetal to the point 

 of hemorrhage (ligation by continuity); e.g., in hemorrhage 

 from one of the arteries in the interior of the head the carotid 

 is ligated. 



(b) Compression of the Vessels by Suture or Bandage, 

 as a rule, checks parenchymatous and capillary hemorrhage. Some- 

 times strong pressure upon the bleeding vessels can be obtained 

 by tamponading a wound. Bleeding may be checked tempo- 

 rarily by pressure with the fingers or hand (digital compression), or 

 by applying an elastic tubing (Esmarch bandage) or a rubber 

 bandage (Martin's bandage) between the wound and the heart. 

 Methods of arresting hemorrhage peculiar to veterinary medicine 

 are the use of clamps and of the emasculator in castration. The 

 formerly employed tourniquet (a compress fastened with a girdle) 

 and the so-called acupressure (compression by a needle inserted in 

 the tissues in a transverse direction, laterally and above or below 

 the bleeding vessel) are now scarcely used. 



(c) Torsion of the Bleeding Vessel loosens the intima and 

 media, which roll inward, and also draws the adventitia together, 

 narrowing or closing the lumen of the vessel. Torsion is carried out 

 in two ways : the bleeding vessel is grasped with the clamp forceps 

 and revolved on its axis for some time, or the surrounding soft 



