THE MOVEMENTS OF THE STOMACH 75 



subject of interest. Nearly eighty years ago William 

 Beaumont published his observations upon the stomach of 

 Alexis St. Martin, a young Canadian trapper, who had 

 suffered a gunshot wound in the left side, in consequence 

 of which he had a permanent gastric fistula. The impres- 

 sion which went abroad from this celebrated case has 

 seemed to convey to the less scientific writers the idea that 

 the pylorus has a power almost akin to intelligent inspec- 

 tion whereby it permits the passage of certain portions of 

 the chyme and refuses egress to other portions. This 

 notion recalls amusingly the teaching of Van Helmont, 

 in the seventeenth century, that the soul of man resides in 

 the pylorus. It cannot be said that all the conditions 

 affecting the discharge from the stomach are entirely clear, 

 but much progress has been made in this direction. 



The sphincter is influenced both by the physical consist- 

 ency and by the chemical reaction of the gastric contents. 

 The contact of coarse, angular particles with the adjacent 

 mucous membrane seems to reinforce its contraction, so 

 that such material tends to be kept longer in the stomach. 

 A more important factor with this sphincter, as with the 

 cardiac, is the acidity of the chyme. It was stated above 

 that when the stomach-contents becomes distinctly acid- 

 ified, the tone of the cardiac sphincter is increased. The 

 acid in this case is acting upon the lining below the irritable 

 ring. Comparison of the two sphincters shows it to be a 

 principle applicable to both that acid acting immediately 

 above favors their relaxation, while acid below causes them 

 to tighten. If this is the main factor in regulating the 

 pylorus, the first opening will occur when the acidity in the 

 antrum has reached a certain point. The next peristaltic 

 wave will transfer a little chyme to the'duodenum. At this 

 instant there will be acid material both above and below 

 the sphincter. The action from below appears to predom- 

 inate, so that closure will be established and maintained 

 until the acid in the duodenum is either neutralized or re- 

 moved somewhat from the pylorus. When the stimula- 

 tion from below is no longer effective the acid above will 



