CHAPTER XXXIV. 



THE MOVEMENTS OP THE OESOPHAGUS* AND 

 INTESTINE. 



Demonstration 12. A rabbit is narcotised by means of 

 urethane (p. 79) t and the oesophagus is exposed. This is accom- 

 plished partly by drawing the trachea to the right by a stout silk 

 ligature passed around it and partly by pulling the oesophagus 

 to the left. The vagus nerve is then followed up to where the 

 superior laryngeal leaves it, and this branch is cut after tying a 

 thread round it as near to the vagus as possible. Stimulation of the 

 laryngeal nerve by a Faradic current excites the act of swallowing 

 and it can be seen that this consists, in order, of a movement of the 

 floor of the mouth, of elevation of the larynx and of the passage of a 

 peristaltic wave along the cesophagus. A record of the peristaltic 

 wave can be obtained by inserting into the lumen of the cesophagus, 

 through a small incision, a thin-walled rubber bag (finger cot), which 

 is connected by tubing with a water manometer and tambour, after 

 distending it with warm water. J 



It is now important to ascertain whether the peristaltic wave 

 can be more readily set up by mechanical irritation of the ceso- 

 phagus or of the pharynx. The stimulation can be produced by 

 stroking with a feather. The cesophagus is finally cut across and a 

 bent pin connected by a thread with a muscle lever attached to the 

 peripheral end of the cut tube. The superior laryngeal nerve is 

 again stimulated. From the results of this observation what con- 

 clusions can be drawn concerning the manner of transmission of the 

 oesophageal peristaltic wave? 



*The action of the base of the tongue, etc., in swallowing may be readily 

 studied in the decerebrate cat, as described on p. 249. 



fFor the success of the observation the anaesthesia must not be too deep. 



Jit is best to tie the finger cot to a rubber catheter so that the end of the cath- 

 eter reaches to the end of the cot. This facilitates insertion of the cot into the 

 cesophagus. It is important to see that the cot becomes uniformly distended with 

 water before connecting with the water manometer. The edges of the incision 

 in the cesophagus should be stitched together so as to hold the instrument in place. 



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