1909.] 



Pathology of Gastric Ulcer. 



239 



The method of producing motor insufficiency which I employ is that of 

 artificial pyloric stenosis. 



The constricting band consists of a piece of rubber tubing as used for 

 constricting the vena cava in my experiments on cardiac dropsy (8). The 

 rubber tubing {\ inch or less in length) is slit open longitudinally and a silk 

 ligature passed round the outside of it ; each free end of the ligature is made 

 to pierce the rubber tubing from without in and again from within out, the 

 ligature now appearing just outside the cut margin. When the ends of the 

 ligature are tied the cut margins come together and the lumen of the tube is 

 restored. By taking a tube of appropriate diameter a thin-walled vessel 

 such as a vein may be constricted to any definite fraction of its diameter 

 required. This cannot be done exactly in the case of the duodenum, because 

 its walls are too thick and it is a contractile organ, so that I have been 

 unable to measure definitely the amount of constriction. The duodena of 

 different cats vary enormously in diameter : a small cat may have a large 

 duodenum and, vice versd, a large cat a small duodenum ; one has therefore to 

 keep a supply of different sizes of tubes ready at each operation. I have 

 found this method completely successful, but since one cannot measure the 

 amounf of constriction the latter has to be guessed, with the result that it 

 is impossible to be absolutely certain what will happen in any given case. 

 If too tight the animal will die, if too slack complete compensation occurs, 

 but in most cases some degree of motor insufficiency results, and after 

 a little practice this end can be accomplished in the vast majority of cases. 

 The abdomen is opened in the middle line under strict antiseptic precautions, 

 and the rubber tubing applied just beyond the pylorus around the first part 

 of the duodenum. 



The animals with motor insufficiency have diminished appetite and lose 

 flesh ; they occasionally vomit, but, curiously enough, vomiting may be 

 practically absent in the higher grades of retention of food, possibly due to 

 depressed sensibility of the sensory nerves of the .stomach. In the slighter 

 grades there is a delay in emptying the stomach, and in these there may be 

 slight dilatation of the stomach or not ; at all events the muscular coat has 

 diminished resistance to stretching after death. A curious feature in these 

 cases is the amount of hair found in the stomach. Hair is always liable to 

 be found in the cat's stomach, due to the animal's habit of licking. In cases 

 of motor insufficiency the hair collects in the stomach, as apparently it is not 

 so able as food to pass the pylorus. The meat is cut up for the animals, as 

 they will not usually eat large pieces. The amount of the appetite is easily 

 estimated by weighing everything the animal is given and everything it 

 leaves. In the higher grades of insufficiency the stomach is usually found 



