86 APPLIED PHYSIOLOGY 



119. Result of intestinal digestion. By the action of 

 the three digestive fluids, the food is dissolved and reduced 

 to a thin, milky form, called chyle. As all food contains 

 many substances wholly indigestible, some solid particles 

 will still remain in the chyle. Digestive action goes on 

 during the whole time that food remains in the intes- 

 tine, but most of the work is done in the small intestine. 

 As it slowly passes down the tube, the liquid parts are 

 taken up until, when it reaches the large intestine, it has 

 become semi-solid again. The expulsion of the solid 

 waste which finally remains is the last act of digestion. 

 It takes about twelve hours for food to pass the length of 

 the small intestine, and thirty-six hours to traverse the 

 large intestine. 



120. What becomes of the ferments. After the ferments of 

 the gastric, pancreatic, and intestinal juices have done their work of 

 digestion, they are probably digested by the new ferments poured out 

 at the next meal, for they are albumin. Bile is a waste product, yet 

 some of its parts are taken up by the blood and carried to the liver, and 

 again poured into the intestine. Thus nature is as economical as 

 possible with the resources of the body. 



121. Perfection of the digestive organs. The mouth is 

 perfectly adapted to masticating just such food as the 

 stomach can readily digest, while it cannot grind such 

 food as corn or hay. The stomach seems a weak, flabby 

 organ, but nature made it of just the right size and strength 

 to do its own proper work. 



The bile is a waste product of the body and yet it is 

 one of the most important agents in digestion. In brief, 

 each part of the digestive system is perfectly adapted to 

 its own work. In lower animals the digestive organs are 

 somewhat modified so as to adapt them to different foods 

 and different modes of eating 



