THE GASTRIC JUICE AND STOMACH DIGESTION. 167 



of the stomach, which is accomplished by the alternate contraction and 

 relaxation of the longitudinal and circular fibres of its muscular coat. 

 The motion is minutely described by Dr. Beaumont, who examined it, 

 both by watching the movements of the food through the gastric fistula, 

 and also by introducing into the stomach the bulb and stem of a ther- 

 mometer. According to his observations, when the food first passes 

 into the stomach, and the secretion of the gastric juice commences, the 

 muscular coat, which was before quiescent, is excited and begins to 

 contract actively. The contraction takes place in such a manner that 

 the food, after entering the cardiac orifice of the stomach, is first car- 

 ried to the left into the great pouch of the organ, thence downward and 

 along the great curvature to the pyloric portion. At a short distance 

 from the pylorus, Dr. B. often found a circular constriction of the gastric 

 parietes, by which the bulb of the thermometer was gently grasped and 

 drawn toward the pylorus, at the same time giving a twisting motion 

 to the stem of the instrument, by which it was rotated in his fingers. 

 In a moment or two, this constriction was relaxed, and the bulb of 

 the thermometer again released and carried, together with the food, 

 along the small curvature of the organ to its cardiac extremity. This 

 circuit was repeated so long as any food remained in the stomach ; 

 but, as the liquefied portions were successively removed toward the end 

 of digestion, it became less active, and at last ceased altogether when 

 the stomach had become completely empty, and the organ returned to 

 its ordinary quiescent condition. 



It is easy to observe the muscular action of the stomach during diges- 

 tion in the dog, by the assistance of a gastric fistula, artificially estab- 

 lished. If a metallic catheter be introduced through the fistula when 

 the stomach is empty, it must usually be held carefully in place, or it 

 will fall out by its own weight. But immediately upon the introduction 

 of food, it can be felt that the catheter is grasped and retained with 

 some force, by the contraction of the muscular coat. A twisting or 

 rotatory motion of its extremity may also be frequently observed, similar 

 to that described by Dr. Beaumont. This peristaltic action of the 

 stomach, however, is a gentle one, and not at all active or violent in 

 character. We have never seen, in opening the abdomen, any such 

 energetic or extensive contractions of the stomach, even when full of 

 food, as may be easily excited in the small intestine by the mere con- 

 tact of the atmosphere, or by pinching with the blades of a forceps. 

 This difference in activity between the peristaltic movement of the 

 stomach and that of the intestine corresponds to the difference in its 

 object and result. In the intestine the peristaltic action carries the 

 semifluid contents of the alimentary canal continuously from above 

 downward ; in the stomach it produces a kneading effect upon the mas- 

 ticated food, and mixes it intimately with the gastric juice. This action 

 of the stomach, accordingly, though quite gentle, is sufficient to pro- 

 duce a constant churning movement of the food, by which it is carried 

 back and forward to every part of the stomach, and incorporated with 



