SALIVARY AND GASTNIC FISTULA. 235 



The wound is then dressed with cotton and collodion and the outer shield of the 

 cannula screwed on, but not so far as to press on the wound. The tube of the 

 cannula is closed by the screw-in stopper. 



Demonstration 11. In about a week, when the wound will 

 usually have healed, the dog is placed on the observation holder (Fig. 

 69) and the following observations are made. A pledget of absorbent 

 cotton attached to a hsemostat is passed into the stomach and 

 gently moved over the mucosa; the nature and reaction of the 

 secretion which adheres to it after removal is observed. A thin- 

 walled rubber bag attached to a glass tube is carefully passed into 

 the stomach through the fistula and filled with warm water. The 

 tube, leading out of the fistula, is connected with a water mano- 

 meter, the free limb of which is attached by tubing to a sensitive 

 tambour arranged to inscribe its movements on a drum. Observa- 

 tions are now made on the hunger contractions. (It may be 

 necessary to wait some time before these appear). When satis- 

 factory records have been secured the animal is teased by tempting 

 it with appetising food and the effect on the contractions noted. 



The rubber bag is now removed and the reaction of the secretion 

 adhering to it tested by means of litmus paper. 



These observations on hunger contractions in a dog should be 

 supplemented by similar ones on man. For this purpose a thin 

 rubber bag is firmly tied on a narrow stomach tube and passed 

 down the oesophagus until the bag lies in the stomach. The bag is 

 then distended by air (cf . Carlson) and the outer end connected with 

 a water manometer and tambour. The observation should be made 

 on a person who has not taken food for some hours previously. 



