694 OPERATIONS. 



placed over the principal artery or arteries of the part, so as to 

 increase the effect of the pressure ; but this arrangement is seldom 

 necessary in horse practice. 



As a tight tourniquet more or less stops the passage of blood 

 underneath it, there will be comparatively little bleeding from a 

 wound made on the limb at a spot below the tourniquet. The 

 occurrence of this bleeding can be almost entirely prevented, by 

 the previous application of an Esmarch bandage, which consists 

 of a thin india-rubber band about 2^ inches broad and 8J feet 

 long. It is rolled tightly round the leg, from below upwards ; 

 beginning at the pastern and ending just above the knee (Fig. 

 181, p. 695). A tourniquet is then put on immediately above the 

 bandage, which is taken off, by undoing it from below upwards. 

 The application of this bandage drives away the blood, which the 

 tourniquet prevents from returning ; the result being that the part 

 below the tourniquet becomes comparatively bloodless. If the 

 operation has to be performed higher up the limb, the bandaging 

 can be continued by the use of a second bandage of the same kind. 

 Although a bloodless condition of the part may appear at first 

 glance to be a great a,dvantage, especially to an inexperienced 

 operator, it has serious drawbacks, when the wound has to be 

 made in a part containing numerous and important blood-vessels, 

 because it greatly increases the difficulty of distinguishing arteries, 

 veins, and nerves from each other. The operator is sometimes 

 obliged to remove the tourniquet, in order to re-establish the 

 circulation of blood, so that he may be able to find out the exact 

 situation of the arteries, or see what small arteries have been cut. 

 Also, the use of a tourniquet and Esmarch bandage is apt to give 

 rise to extensive bleeding after the operation, when these appli- 

 ances have been removed. 



I have already pointed out that the application of a tourniquet 

 should be employed only for a short time; because destructive 

 changes and finally death of the part will quickly ensue, if it be 

 long continued. 



Tracheotomy. 



GENERAL REMARKS. — ^Tracheotomy is the operation of 

 making an opening from the outside of the throat into the wind- 

 pipe (trachea) with the object of relieving obstruction to breathing 

 situated above the opening. It may be temporary for acute 

 difficulty of breathing which threatens the life of the animal ; or 

 permanent for chronic affections, such as roaring. As the opening 

 has a constant tendency to become closed, we are obliged, in order 

 to counteract this effort at repair by the wounded tissues, to adopt 



