THE CESOPHAGUS 53 



render these courses almost impossible, and the only course of treatment 

 which remains is the passage of the probang. 



Passage of the Probang 



In passing this instrument a careful reference to the plate representing 

 the longitudinal section of the parts will show that the safe course is to 

 keep close to the roof of the mouth, and that the first difficulty is met 

 with at the entrance to the cesophagus. Noting that, excepting when 

 the animal is in the act of swallowing, the glottis is open, and there is a 

 danger of the probang entering the trachea instead of the oesophagus, 

 it is therefore best not to attempt to force the passage of the instrument 

 just at this stage, but to wait until the animal, of its own accord, 

 performs the act of deglutition, when the probang will pass naturally 

 into the cesophagus and the glottis will be closed. 



That it is in the a'sophagus will be evident by the tact that it will 

 glide smoothly away from the operator, and not slip suddenly from his 

 grasp, as it would do if it were in the trachea, since the walls of the 

 latter are rigid and its lumen always patent. 



Upon reaching the obstacle gradual pressure should be applied 

 in forcing it down the tube, deliberating particularly at the entrance 

 to the stomach on account of the peculiar arrangement of the fibres 

 here already referred to. 



The obstruction may be placed in the cervical portion of the cesophagus. 



In this case its position is easily determined by the fact that it 

 causes a swelling which, if the cesophagus is not ruptured, is well defined. 

 If the cesophagus is ruptured, however, the swelling is diffused and 

 extends downwards over the side, and even the under aspect of the 

 trachea, and upwards over the mastoido-humeralis muscle. Moreover, 

 the swelling is emphysematous. 



Failing other methods of removal, e.g., manipulation, passage of 

 probang, etc., the operation of cesophagotomy may be performed. 



