DIGESTION AND ABSORPTION OF FA TS. 443 



Minkowski and Abelmann 1 found, after complete removal of the 

 gland in dogs, that on an average 44 per cent, of proteid was absorbed ; 

 after partial removal, 54 per cent. The amount of absorption was much 

 increased on giving raw pancreas with the food. Sandineyer 2 obtained 

 similar results. On removal of all but one-fifth to one-fourth of the gland 

 (the portion remaining behind not being in communication with the 

 intestine), 60 to 70 per cent, of proteid was still absorbed, and, on adding 

 a supply of finely-minced pancreas to the food, the absorption of proteid 

 became almost normal. 



DIGESTION AND ABSORPTION OF FATS. 



The pancreatic juice is the only digestive secretion which contains an 

 enzyme possessing a chemical action on the neutral fats. 3 This action 

 consists in splitting the fats into fatty acids and glycerin, 4 and may 

 be demonstrated in one of the following ways : 



1. A neutral fat is first obtained, e.g., by thoroughly shaking olive 

 oil with sodium carbonate solution and ether, pipetting off the ethereal 

 layer, filtering if necessary, and finally allowing the ether to evaporate, 

 when a neutral fat is left behind. This is mixed either with fresh 

 pancreatic juice, or an extract of the fresh gland prepared as already 

 described, and the mixture, after being coloured blue by the addition 

 of litmus, is placed in a bath at 37 to 40 C. The alkaline reaction is 

 seen gradually to change into an acid one. 



2. Instead of adding litmus, after the mixture of neutral oil and 

 pancreatic juice, or extract, has digested for some time (half to two hours), 

 sodium carbonate solution is added (which converts the free fatty acids 

 formed into soaps), and the unattacked fat is removed by repeated 

 extraction with ether. The residue is next treated with dilute 

 sulphuric acid, setting free again the fatty acids, which are extracted 

 with fresh ether, and recovered after its removal by evaporation. 



3. The formation of free fatty acid may be also qualitatively shown, 

 by removing water from the fresh, finely-divided gland, with 90 per cent, 

 alcohol, drying it with filter paper, and then covering it with a neutral 

 ethereal solution of butter, obtained by shaking up milk or cream with 

 ether and a solution of caustic soda. When this material is kept for a 

 short time at 37 to 40 C., a distinct odour of butyric acid appears ; and if 

 the mixture has been previously rendered blue by litmus, this turns red. 



Form in which fats are absorbed from the intestine. There has 

 been much discussion as to the extent to which the decomposition 

 of the fats by the pancreatic enzyme, as above described, takes place 

 in the intestine ; and also as to the subsequent fate in the intestine 

 of the fatty acids formed therein. According to the views held on 



1 " Ueber die Ausnutzung der Nahrungsstoffe nach Pancreasextirpation," Inaug. Diss., 

 Dorpat, 1890 ; Jahresb. ii. d. Forlschr. d. Thier-Chem,, Wiesbaden, 1890, Bd. xx. S. 45. 

 -Ztschr.f. Biol, Miinchen, 1895, Bd. xxxi. S. 35. 



3 Fats are said to undergo a certain amount of decomposition into fatty acids in the 

 stomach (Marcet, Proc. Roy. Soc. London, 1858, vol. ix. p. 306 ; Cash, Arch. f. Anat. u. 

 Physiol., Leipzig, 1880, S. 323) ; the cause of this decomposition is unknown, but it is 

 probably bacterial during the first stage of gastric digestion. 



4 Bernard, Compt. rend. Acad. d. sc., Paris, tome xxviii. ; Arch. gen. de med., Paris, 

 1849; "Mcmoire sur le pancreas," Paris, 1856; "Lecons de physiologic expe'rimentale," 

 tome ii. p. 256. For the chemical equations representing such a decomposition, see 

 Chemistry of the Fats, p. 1 9. 



