ABSORPTION OF FATS. 537 



of soaps. According to CRONER the absorption of soaps occurs only 

 in the lower parts of the small intestine. 



The importance of the bile, the soaps, and the alkali carbonates has 

 been closely studied, principally in the very thorough investigations of 

 PFLUGER. He has quantitatively determined the solvent power of 

 the above-mentioned bodies each alone as well as different mixtures 

 of these for the various fatty acids, and has closely studied the mode 

 of action of the bile. From his investigations he has arrived at the 

 conclusion that no unsplit fat is absorbed, that all fats, before their 

 absorption, must first be split into glycerin and fatty acids, and that the 

 bile, on account of its solvent power for soaps and fatty acids, is sufficient 

 for the absorption of large quantities of fat eaten. The object of the 

 formation of an emulsion is, according to this view, that the fat in this 

 condition forms such a large surface for the action of the steapsin or 

 the fat-splitting agents. The possibility that all the fat must be first 

 split and that no unsplit fat is absorbed is, according to these researches, 

 not to be denied. 



The next question is whether all the fat or the greater part of it 

 passes into the blood through the lymphatics and the thoracic duct- 

 According to the researches of WALTHER and FRANK 1 on dogs, it seems 

 that only a small part of the fats, or at least of the fatty acids fed, 

 passes into the chylous vessels; but these observations can hardly be 

 applied to the absorption of neutral fats, or to the absorption in man 

 under normal circumstances. MUNK and RosENSTEiN, 2 in their inves- 

 tigations on a girl with a lymph fistula, found 60 per cent of the fat 

 ingested in the chyle, and of the total quantity of fat i^n 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 the 

 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 ARNSCHiNK, 3 

 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 



1 Walther, Arch. f. (Anat. u.) Physiol., 1890; Frank, ibid., 1892. 



2 Virchow's Arch., 123. 



3 Munk, Virchow's Arch., 80 and 95; Arnschink, Zeitschr. f. Biologic. 



