SURGICAL OPERATIONS. 301 



In cattle the operation is usually performed on the left jugular 

 vein, which is large and is easily rendered so prominent as to prevent 

 the jDOsibility of mistake by tying a cord around the neck below the 

 place where the incision is to be made. (PI. XXVII, fig. 4.) The 

 rope should be tied in a slip knot, so as to admit of its being easily 

 undone, or a rope used with a loop at one end and a series of good- 

 sized knots at the other, the loop and knots to be used as buttons and 

 buttonholes. The proper instrument to use is a large-blade fleam. 

 (PI. XXVII, fig. 3.) After the animal is secured the operator stands 

 by the shoulder, holds the fleam in his left hand, the blade just short 

 of touching the skin and parallel to the direction of the vein, and the 

 stick or mallet with which to strike it in his right ; one quick, sharp 

 blow should be sufficient. If the hair is long, it is a wise precaution 

 to moisten and smooth it down. 



^Tien sufficient blood has been withdrawn the rope is removed and 

 the orifice closed by means of a pin inserted through the lips of the 

 incision i7i the skin only, and a piece of fine string or tow wound 

 either over or under it in the shape of a figure 8, or in a circle be- 

 tween the skin and the pin (PI. XXVIII, fig. 10), the point of which 

 should be clipped off. To prevent the animal from rubbing the part 

 and tearing or dislodging the pin, it is advisiible to tie the head up for 

 a couple of days, providing tlie animars health will admit of it, 

 after which the pin may be removed and the wound left to heal in 

 the usual manner. 



Before leaving the subject it may be well to add that as the good 

 effects derived from bleeding depend more on the quickness with 

 which the blood is drawn than on the quantity extracted, it is of 

 importance that a liberal opening should be made into the blood 

 vessel and the blood allowed to flow until a perceptible impression 

 has been made on the pulse. 



SETOXING. 



Setons are used in cattle for various purposes, of which perhaps 

 the most common is as a preventive in anthrax or blackleg, when a 

 seton is usually inserted in the dewlap. This is done not to afford 

 exit to any poisonous discharge from the system, as is generally sup- 

 posed, but to cause a sufficient amount of inflammation to increase the 

 coagulating properties of the blood, which in these diseases becomes 

 altered (as described elsewhere), notably losing its viscidity and in 

 consequence oozing through the walls of the blood vessels. For this 

 purpose the seton should be deeply inserted and should be dressed 

 daily with turpentine or common blister. 



The ordinarv' use of a seton is for a different object, as, for in- 

 stance, to keep up constant drainage from a cavity containing matter, 



