THE GUTTURAL POUCHES 8i 



chronic discharges of the kind, inasmuch as its odour is by no means 

 offensive. 



The two pouches, as already stated, are in close proximity to one 

 another, and when one pouch is distended in a marked degree it bulges 

 out laterally, exerts pressure upon the other pouch, and a swelling 

 appears on the opposite side of the head, which might lead one astray 

 by suggesting that both pouches are affected. 



In extreme cases of impaction of a pouch the animal also inclines 

 its head to the opposite side to relieve the pressure of the distended 

 pouch upon the various and important anatomical structures which 

 surround it. 



Positive diagnosis may be frequently made by means of Gunther's 

 catheter. This is a long brass tube, the extremity of which is rounded 

 and closed in order that it may perform the function of the extremity 

 of a sound. Communication between the bore of the tube and the 

 exterior, however, is established through two apertures, placed opposite 

 to one another just behind the rounded extremity. The tube is about 

 two feet long, its point is slightly curved, and the other extremity is 

 indexed in such a manner that the operator is enabled to ascertain when 

 the end of the catheter arrives at the entrance to the eustachian tube. 

 The free edge of the valve-like piece of cartilage guarding the entrance 

 to the latter, it will be remembered, is directed towards the posterior 

 meatus, and along this part of the nasal chamber the catheter must 

 therefore be passed. 



The opening into the eustachian tube and the temporal canthus 

 are equidistant from the anterior nares, and thus the operator, by 

 measuring the distance from this canthus to the nasal opening, is 

 enabled to ascertain the length of tube which must be passed into 

 the meatus before the eustachian orifice is reached, and to regulate 

 the index on the catheter accordingly.* 



* A further reference to Plate III., representing a longitudinal section ot the head, will 

 greatly assist in the operation of passing this instrument. 



