308 DISEASES OF CATTLE. 



that the instrument used should be sharp and scrupulously clean. A 

 neglect of the latter precaution is apt to lead to very serious conse- 

 quences. 



SETONING. 



Setons are used in case of the ox tribe 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 not done to 

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

 supposed, 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 ordinary use of a seton is for a different object, as, for instance, 

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

 act as a stimulant or counterirritant. To insert a seton, the place of 

 entrance and exit having been decided on, with the finger and thumb 

 make a small fold of the skin transverse to the direction the seton is to 

 be inserted, and cut it through, either with a sharp knife or a pair of 

 scissors (this should be done at both the entrance and exit) ; then with a 

 steady pressure and slight lateral movement insert the seton by means 

 of a seton needle. (Plate xviu, Figs. 1 and 2.) The seton should consist 

 of a piece of strong tape, varying in breadth according to circumstances, 

 and should be kept in place either by a knot on each end or by tying 

 the ends together. 



Setons should be gently moved once a day after suppuration is set 

 up, and they should not be allowed to remain in over three weeks, or a 

 month at the outside. 



TRACHEOTOMY. 



This operation consists of making an opening in the trachea or wind- 

 pipe. It is indicated whenever there is an obstruction from any cause 

 in the upper part of the respiratory tract which threatens the death 

 of the animal by asphyxia (suffocation). The mode of procedure is as 

 follows : Have an assistant extend the animal's head as far as possible 

 to make the trachea tense and prominent; make a longitudinal incision 

 about 2 or 2| inches long through the skin and deeper tissues at the 

 most prominent part of the trachea, which is about the middle or upper 

 third ; the edges of the skin should be held apart to allow the intro- 

 duction of the tenaculum or curved needle through the rings of the 

 trachea, and a circular piece of the trachea removed, large enough to 

 allow of the introduction of the tracheotomy tube. (Plate xxvii, Figs. 

 1 and 2.) The latter should be removed once or twice daily and 

 cleansed, and the wound dressed antiseptically. To ascertain when it 

 is time to discontinue the use of the tube and to allow the wound to 



