HYOVERTEBKOTOMY. 457 



In respect to glanders, moreover, the bad odor, the thick, gru- 

 mous nasal discharge, and the soreness and dullness on percussion 

 of certain parts of the face, will in many cases serve to identify 

 and distinguish a pathological condition of the sinuses very dif- 

 ferent from that of the disease we are considering. Gohier and 

 Vatel also refer to guttural tympanitis, or dilatation of the pouches 

 by air, as a featm-e of their -disordered condition. The amount of 

 pus collected in the pouches varies in different cases to such an 

 extent that from only a trifling degree of dilatation it may be suf- 

 ficiently extensive to produce a sensible projection of the sac below 

 the parotid. This dilation furnishes a guide for the determination 

 of the proper point at which to make the puncture, whether in the 

 upper, in the middle, or in the lower part of the pouches. The 

 uj)per operation is hyovertebrotomy proper. Besides these three 

 modes of operation, Gunther has proposed a fourth method which 

 consists in penetrating the pouches through the nasal cavities. 



Upper operation — Hyovertebrotomy p)roper. — As described by 

 Chabert and Fromage de Feugre, this is one of the finest and most 

 delicate operations of veterinary surgery. Extremely so when per- 

 formed on horses whose pouches are healthy and normal in size, 

 it loses a great deal of its apparent difficulty when these are full of 

 pus with prominent and well developed walls. The nerves and 

 blood vessels which surround them are then easily pushed aside 

 from their position, and the lobules of the parotid are more or less 

 separated. 



The instruments required for this operation are: a pair of 

 scissors, a convex and a straight bistoury, a dissecting forceps, an 



Fig. 398.— Curved Trocar, or Hyovertebrotome. 



S probe, or preferably, the curved trocar, the hyovertebrotome 

 (Fig. 398), and a piece of tape. Artery forceps and ligatures 

 ought to be always within reach. 



Bouley, Zundel and others recommend that the animal should 

 be kept in the standing position with simply a twitch on the lip, 



