102 STUDIES IN CLINICAL PHYSIOLOGY 



occurs when hard indigestible articles are taken as 

 food, and the powerful peristalsis against a spas- 

 modically contracted pylorus causes pain. 



Hyperchlorhydria in animals induces prolonged 

 spasm of the pylorus, lasting over many hours, 

 because the acid in the duodenum takes so long 

 being neutralized. 



For clinical purposes, skiagrams after a bismuth 

 meal (one or two ounces of bismuth oxychloride in 

 milk or porridge) are of distinguished value. The 

 patient should be examined both standing and lying 

 down, and at varying intervals. Gastroptosis, gastric 

 dilatation, pyloric spasm, and hour-glass contraction 

 become quite evident. In the last case the con- 

 nection of the two sacs is between their upper portions, 

 not at the lowest point — the latter appearance is of 

 little significance. Percussion and auscultation may 

 frequently be proved inaccurate by skiagraphy. 



MOVEMENTS OF THE INTESTINE. 



We have always known that the small intestine is 

 continually in movement, the main character of the 

 movement being an onward sweeping wave called 

 peristalsis, carrying the bowel contents from the 

 stomach to the colon. Peristalsis consists of a wave 

 of relaxation pursued by a wave of constriction. It 

 is controlled by a purely local mechanism, and will 

 go on after all nerves have been severed, or even 

 after taking the intestines right out of the body. 

 After cutting the bowel across, the wave is stopped 

 at the point of division. Fortunately for the practice 

 of end-to-end anastomosis of the intestines, any 



