IQ$ Human Physiology. 



Liquids, and the liquid portions of our food are rapidly ab- 

 sorbed by the veins of the stomach and pass into the circula- 

 tion. All intoxicating liquors are thus taken up and are in a 

 few moments felt in the brain, and smelled in the breath and 

 perspiration. But the greater part of the food dissolved in the 

 stomach passes, as chyme, into the duodenum, or beginning of 

 the small intestines. 



These, like the stomach, are lined with a mucous membrane, 

 and in it are multitudes of glands pouring secretions into them, 

 and absorbents to take up and carry off the matter of nutrition. 

 They have muscular contractions forming what is called their 

 peristaltic action a worm-like succession of contractions 

 which force the contained matters downward. There are also 

 on the interior of some animal intestines myriads of cilia, or 

 little hair-like bodies, attached to the cells of the living 

 membrane (Fig. 40), and these are in 

 perpetual rapid motion, brushing or sweep- 

 ing forward the fluid matter. The mode 

 of their action is utterly inexplicable. 

 The microscope gives us no clue to it. 

 We know only that it is, and that similar 



organs are found in all animals, down to 

 EPITHELIUM. . 



the lowest forms of infusoria and even in 



vegetable spores. It is one of the millions of the mysteries of 

 life. 



When the chyme has left the stomach it soon encounters and 

 is mingled with another secretion that of a large gland called 

 the pancreas known in animals as the " sweet-bread " simi- 

 lar to the salivary glands, and furnishing a large quantity, 

 probably about ten pounds daily, of a clear, slightly viscid and 

 alkaline fluid. Its office seems to be to convert starch into 

 sugar, and oil or fat into soap, so that they can be dissolved. 

 To form the gastric and pancreatic juices the chloride of soda 

 has been decomposed, furnishing hydrochloric acid to one and 



