MECHANICAL PHENOMENA. 51 



Whether they ure merely exaggerated forms of the normal 

 movements or differ materially from the latter cannot there- 

 fore be said with definiteness. That food takes a very much 

 shorter time to pass the length of the alimentary tract under 

 the influence of saline cathartics is a well-known clinical 

 fact, and has often enough been proven experimentally by 

 feeding inert substances and determining the time required 

 before they appear in the fseces. The greater fluidity of the 

 stools we must, in the face of these recent experiments, 

 attribute to the increased secretion of fluid into the intestine 

 and not to a decreased absorption. That less of the food 

 is absorbed when saline cathartics are administered shortly 

 after a meal is in part dependent, no doubt, upon the in- 

 creased velocity with which the food traverses the bowel. 

 Less time is allowed in consequence for the products of 

 digestion to diffuse through the intestinal mucosa. 



The cause of the pain (colic) which follows the ingestion 

 of the saline (and other) cathartics is also not entirely under- 

 stood. S. J. MELTZER has made an interesting study of the 

 subject. This author holds the increased force of the con- 

 tractions and their irregularity responsible for the pain 

 in all forms of intestinal colic. 



Further work with the x-rays would teach us much regard- 

 ing the movements of the intestines as a whole under ab- 

 normal conditions. That after the administration of the 

 saline cathartics it is probably a rapid sweeping peristalsis 

 which advances the food through several coils of intestine, 

 instead of the normal slow peristalsis which moves the food 

 onward only a short distance, seems very probable from a 

 statement made by CANNON,! who observed this form of 

 movement in the small intestine as a regular consequence of 

 the injection of soap-suds. Many of the soaps resemble in 

 their action the saline cathartics. 



12. The Fate of Nutrient Enemas. While certain clinical 



1 CANNON: American Journal of Physiology, 1902, VI, p. 260. 



