tESOPHAGUS. 735 



PASSING THE PPvOBANG. 



Passage of the probang is called for in cases of marked tympanites, 

 suspected dilatation or contraction of the cesophagns, and accidental 

 obstruction. Special or improvised instruments may be used, accord- 

 ing to circumstances. 



The animal is secured in a standing position with the head 

 extended, on the neck and in a straight line with the body. A gag 

 is placed in the mouth and the tongue is grasped and withdrawn by 

 an assistant, whilst the operator, having carefully oiled the probang, 

 passes it through the gag towards the back of the pharynx. 

 Violence should be avoided, the probang being gently slid along 

 the centre of the vault of the palate. When the animal makes 

 swallowing movements, the apparatus is slowly pushed onwards. 



This manipulation, though simple, requires some dexterity, because 

 at the moment when the instrument enters the pharynx the animal 

 often thrusts it to one side or the other with the base of its tongue, 

 bringing it between the molar teeth, and so crushing, or at least 

 injuring it. 



The passage of hollow probangs gives comparatively little relief 

 in cases of tympanites, because the probang is almost always ob- 

 structed by semi-digested material from the rumen, or plunges into 

 the semi-solid masses of food contained therein. 



^Vhen the cesophagus is dilated at a point within the thorax, the 

 progress of the probang is checked by the accumulated food material, 

 and it becomes possible to determine approximately the place where 

 the dilatation occurs. In the same way, should a slender probang 

 be arrested at a given point in the oesophagus, this indicates that 

 there is contraction of the tube at that point. 



In cases of obstruction the cupped probang is always arrested by 

 the foreign body. Efforts to thrust the latter onwards should always 

 be made with great caution, otherwise the oesophagus may be greatly 

 distended or its walls even ruptured. 



CRUSHING THE FOREIGN BODY. 



No attempt should be made to crush a foreign body within the 

 cervical portion of the oesophagus unless it is quite certain that that 

 body is of comparatively soft character. Crushing may be performed 

 by lateral pressure with the fingers within the region between the two 

 jugular furrows, or mechanical means may be adopted. 



In the latter case a small piece of board is applied to one side of 

 the neck behind the foreign body, whilst gentle blows are given from 



