514 DIGESTION. 



fat ingested in the chyle, and of the total quantity of fat In the chyle 

 only 4-5 per cent existed as soaps. On feeding with a foreign fatty 

 acid, such as erucic acid, they found 37 per cent of the introduced body 

 as neutral fat in the chyle. Not all the fat introduced is found in 

 fche chyle, and there is always a not inconsiderable part of the absorbed 

 fat whose fate we are not able to follow. 



The completeness with which fats are absorbed depends, under nor- 

 mal conditions, essentially upon the kind of fat. In this regard it is 

 known, especially from the investigations of MUNK and AENSCHiNK, 1 

 that the varieties of fat with high melting-points, such as mutton-tallow, 

 and especially stearin, are not so completely absorbed as the fats with 

 low melting-points, such as hog- and goose-fat, olive-oil, etc. The kind 

 of fat also has an influence on the rapidity of absorption, as MUNK and 

 ROSENSTEIN found that solid mutton-fat was absorbed more slowly 

 than fluid lipanin. The extent of absorption in the intestinal tract is, 

 under physiological conditions, very considerable. In the case of a 

 dog investigated by VOIT it was found that out of 350 grams of fat 

 (butter) partaken, 346 grams were absorbed from the intestinal canal, 

 and according to the investigations of RuBNER 2 the human intestine 

 can absorb over 300 grams of fat per diem. The fats are, according 

 to RUBNER, much more completely absorbed when free, in the form of 

 butter or lard, than when inclosed in cell-membranes, as in bacon. 



CLAUDE BERNARD showed long ago with experiments on rabbits in 

 which the ductus choledochus was made to open into the small intestine 

 above the pancreatic duct, that after food rich in fats the chylous vessels 

 of the intestine above the pancreas passages were transparent, while 

 below they were milk-white, and also that the bile alone cannot produce 

 an absorption of the emulsified fat without the pancreatic juice. DASTRE 3 

 has performed the reverse experiment on dogs. He tied the ductus 

 choledochus and adjusted a biliary fistula so that the bile flowed into 

 the intestine below the mouth of the pancreatic passages. On killing 

 the animal after a meal rich in fat the chyious vessels were first found 

 milk-white below the discharge of the biliary fistula. From this DASTRE 

 draws the conclusion that a combined action of the bile and pancreatic 

 juice is important in the absorption of fats a conclusion which stands 

 in accord with the experience of many others. 



Through numerous observations of many investigators, such as 

 BIDDER and SCHMIDT, VOIT, ROHMANN, FR. MULLER, I. MuNK, 4 and 



1 Munk, Virchow's Arch., 80 and 95; Arnschink, Zeitschr. f. Biologie, 26. 



2 Volt, Zeitschr. f. Biologie, 9; Rubner, ibid., 15. 



3 Arch, de Physiol. (5), 2. 



4 F. Miiller, Sitzungsber. der phys.-med. Gesellsch. zu Wiirzburg, 1885; I. Munk, 

 Virchow's Arch., 122. See also footnotes 4, p. 495 and 1, p. 496. 



