OIL OK FAT. 71 



the pancreatic juice disappears, and in its stead the intestinal 

 juice, as alleged by many, continues the same action in a less 

 energetic manner. The starch granules soften on their surface, 

 and, while they dissolve, become changed to dextrine and then 

 into sugar. ^ Lamellse separate from the granules in a greater 

 or less state of disintegration, isolated shreds being often per- 

 ceptible by the microscope after the application of iodine. The 

 farther the starch descends in the intestine, the smaller do the 

 granules appear, in consequence of this gradual solution of 

 their surface. The dextrine first formed is so rapidly changed 

 into sugar that it is rarely found in the intestines. Thus the 

 greater part of the starch contained in the food finds its way 

 into the blood, not by the lacteal vessels, but by direct absorp- 

 tion into the capillaries of the intestinal mucous membrane, 

 whence it passes into the radicles of the portal vein to be 

 transmitted through the liver. Some part of the starch con- 

 tained in the aliment passes, even in the small intestine, into 

 lactic acid, and in the lower portions of the small intestine, 

 and particularly in the great intestine, into butyric acid ; and 

 under these forms it is even more rapidly absorbed into the 

 blood than when changed into sugar. It appears that nearly 

 the same rules as to the absorption of saccharine matter 

 prevail, whether it be formed from starch within the alimentary 

 canal, or introduced as an integral part of the aliment under 

 the forms of glucose or grape-sugar, sucrose or cane-sugar, or 

 sugar-of-milk. 



Vegetable mucus or bassorine, and vegetable jelly or 

 pectine, are said, like gum, to be totally unaffected by the 

 digestive fluids. 



Oil or Fat. With respect to the digestion of oil or fat, diffi- 

 culties present themselves. No material changes take place on 

 oil either in the mouth or in the stomach, for both the saliva 

 and the gastric juice are devoid of any effect, either mechanical 



