426 PHYSIOLOGICAL CHEMISTRY. 



C 3 H 6 .(C 18 H 35 0) 3 3 + 3H 2 = 3C 18 H 36 2 + C 3 H 5 (OH) 3 . 

 Stearin. Water. Stearic acid. Glycerin. 



A portion of the alkali present then unites with the fatty acid to 

 form a dialyzable soap. 



Amylopsin acts upon starches, converting them into maltose. The 

 change is one of hydration : 



2C 6 H 10 6 + H 2 = C 12 H 22 O n . 

 Starch. Maltose. 



Any albuminoids that may have escaped the action of the gastric 

 juice are converted into peptones by trypsin. In this process, which 

 is apparently one of hydration, the intermediate compound syntonin 

 is not formed. The fourth, assumed and unnamed ferment of pan- 

 creatic juice, has the property of coagulating casein. 



In addition to the above considered digestive fluids, there are the 

 intestinal juices. They are, however, so small in quantity and so 

 difficult of investigation that little is known of their action. They 

 probably have properties similar to the pancreatic juice, though 

 weaker than that secretion. By the combined action of the various 

 digestive fluids, the chyme is gradually converted into chyle. It is a 

 milky-white, or occasionally a yellowish fluid, having an alkaline 

 reaction, a faint smell, a saltish taste, and a specific gravity varying 

 from 1.007 to 1.022. It is this chyle which is absorbed by the intes- 

 tinal villi, and forms the material from which the blood is constantly 

 renewed. 



Absorption. Assimilation. All forms of food that are dialyzable 

 when taken into the stomach, or that are there converted into dia- 

 lyzable compounds, are, for the most part, taken directly into the 

 radicles of the portal vein by osmose. The products of intestinal 

 digestion make their way partly into the bloodvessels and partly into 

 the lacteals. It has been shown that the larger portion of fats which 

 are not dialyzable get into the lacteals as fats, and not as dialyzable 

 soaps. At present we do not understand the process by which this 

 absorption of emulsified fats takes place. 



All material absorbed by the lacteals is carried by the thoracic duct 

 and poured into the left subclavian vein. All material taken up by 

 the portal vein is first carried to the liver. In the liver the maltose 

 undergoes dehydration, being thereby converted into an insoluble 

 compound, isomeric with starch, and termed glycogen. This glycogen 

 is stored up in the liver, and when wanted in the system is recon- 

 verted into soluble maltose. 



