PRINCIPLES OF VETERINARY SURGERY 197 



method, a cord tourniquet will seldom fail to prevent sec- 

 ondary hcemorrhage if left on for three hours. Compression 

 of the metacarpals for two hours will usually permanently 

 arrest a haemorrhage of the foot. 



3rd. By Ligation. — Ligation is the ideal hemostasis. It 

 seldom fails, even in the arrest of the copious flow that oc- 

 curs from such large vessels as the carotid arteries, the 

 jugular veins, the nutrient arteries of large tumors, etc. In 

 surgical operations large vessels should always be ligated 

 before they are cut, instead of depending upon the possibil- 

 ity of accomplishing the feat afterwards. The chief obstacle 

 of ligation is that of grasping the vessel after it has re- 

 tracted into the tissues, and its exact location is masked by 

 the rapid flow of blood into the cavity. 



The ligation should be done with a thread that varies 

 according to the size of the vessel. A large vessel requires 

 a large thread, one that will not cut through the vessel wall 

 before the coagulum has firmly organized. Often, several 

 threads should be applied to the large vessel and these may 

 even be made still more safe by the application of a hemo- 

 static forcep, for twenty-four hours, between the last thread 

 and the main trunk. Ligated large vessels must not be 

 disturbed until the thread has safely sloughed away from the 

 stump. Traction upon the thread earlier may provoke a 

 serious secondary haemorrhage. 



4th. By Forcep Torsion. — Forcep torsion is the ex- 

 pedient made use of during the surgical operation for bleed- 

 ing vessels of nominal size. The small vein or artery is 

 grasped, crushed or twisted, chiefly to cope with the blood 

 that masks the surgical wound, and to eliminate the flow 

 prior to closure of the wound with sutures. This method 

 is not always efifectual. Vessels are often difficult to grasp 

 in certain tissues, and others persist in bleeding even after 

 repeated twistings. The most efifectual results are obtained 



