VE TERINAR T DENTAL S URGER f. 205 



foreign matters that daily collected. The function 

 of respiration which had been mechanically inter- 

 fered with was, after the operation, performed with 

 ease, and at the end of the fourth week he was dis- 

 charged. He has been seen since several times, and 

 found in perfect condition, doing his daily work. 

 TREPHINING STEPS IN THE OPERATION. 



The operation of trephining may be divided into 

 three separate steps: ist, the securing of the animal; 

 2d, the removal of the soft structures ; 3d, the 

 removal of the hard structures. 



i st. Back the animal into a narrow stall, apply 

 a twitch to the upper lip and have it held by an 

 assistant. Another assistant should place one hand 

 across the nostrils, high enough up so as not to inter- 

 fere with respiration, and the other hand across the 

 poll to prevent the animal from making a sudden 

 movement. To trephine successfully, it is not neces- 

 sary to cast the horse, especially if he has never been 

 operated on before. There are, however, instances 

 where it is necessary to cast the animal, but they are 

 exceedingly rare. In four years' practice as a pro- 

 fessional dentist, I have never found it necessary to 

 cast but one animal, and that one had been operated 

 on several times previous to my operating. 



2d. It is advisable to remove a circular piece of 

 skin and subcutaneous tissue somewhat larger than 

 the trephine. Dissect away all the soft structures, 



