Human Physiology. 



soda to the other. In the duodenum these elements re-unite 

 to form common salt, which is absorbed with the food into the 

 circulation ! 



At the same point where the pancreatic duct brings its solvent 

 juice into the intestines, the liver also pours in its supply of 

 bile, which appears to promote the solution of fatty substances 

 and. stimulate the action of the bowels. The bile, however, is 

 an excretion, the result of a purifying process, but here is an 

 instance of matter destined to be cast out of the system, still 

 doing useful work on the way. By the action of these two 

 agents the chyme is converted into chyle, and is ready to be 

 absorbed and converted into blood. 



In Figures 41 and 42 are shown the villi which line the 



Fig. 41. LONGITUDINAL Fig. 42. VILLI AND FOLLICLES OF 



SECTION OF SMALL IN- ILEUM, HIGHLY MAGNIFIED 



TESTINES, SHOWING VlLLI. 



intestines, and distinguish, choose, suck up, and, after what 

 vital change we know not, pass over the nutritive matter to 

 the capillaries and veins, by which it is carried into the circula- 

 tion. Glands are at the same time pouring secretions into the 

 intestines ; and it is so managed that in a vigorous state of the 

 nervous system these two opposite processes go on together 

 without interference. The proper food elements are absorbed, 

 and the refuse is passed on with the excreted waste matters of 

 the system, until these latter, arriving at the end of the larger 

 intestines, are stored there for a convenient time, and then 



