CARBOHYDRATE ABSORPTION. 509 



tion fluids act substitutingly. In this regard ZUNZ and MAYER l found 

 that in dogs (meat digestion) the tying of the pancreatic passages 

 is essentially compensated for by an increased secretion of pepsin and other 

 proteolytic enzymes, and that in this case the demolition of the protein 

 in the stomach goes further than in a normal animal. 



The carbohydrates are, it seems, chiefly absorbed as monosaccharides. 

 Dextrose, levulose, and galactose are probably absorbed as such. The 

 two disaccharides, saccharose and maltose, ordinarily undergo an inver- 

 sion in the intestinal tract and are converted into dextrose and levulose. 

 Lactose is also, at least in certain animals, inverted in the intestine. 

 In other mature animals, on the contrary, if the lactase formation is not 

 excited by milk food, the sugar is not inverted or only to a slight extent 

 (VoiT and LUSK, WEINLAND, PORTIER, ROHMANN and NAGANO), and it 

 probably is absorbed as such in these animals if it does not undergo fer- 

 mentation, or, as ROHMANN and NAGANO 2 assumed, if it is not trans- 

 formed in the intestinal mucosa in some unknown way. An absorption 

 of non-inverted carbohydrates is not improbable, and according to OTTO 

 and v. MERING the portal blood contains, besides dextrose, a dextrin-like 

 carbohydrate after a carbohydrate diet. MoscATi 3 believes that when 

 homogeneous starch solutions are injected intravenously or subcutaneously 

 the starch is taken up by the organs, namely the spleen, liver and lungs, 

 and is utilized as the starch is changed into glycogen. A part of the car- 

 bohydrates is destroyed by fermentation in the intestine, with the forma- 

 tion of lactic and acetic acids and other bodies. 



The different varieties of sugars are absorbed with varying degrees 

 of rapidity, but as a general thing absorption occurs very quickly. This 

 absorption takes place more quickly in the upper part of the intestine than 

 in the lower part (ROHMANN, LANNOIS and LEPINE, ROHMANN and NA- 

 GANO 4 ) . It is generally admitted that the simpler sugars are more quickly 

 absorbed than the disaccharides, while the reports as to the absorption 

 of the disaccharides differ somewhat (HEDON, ALBERTONI, WAYMOUTH 

 REID, ROHMANN and NAGANO). There seems to be no doubt that lac- 

 tose is absorbed more slowly than the two other disaccharides. Accord- 

 ing to the extensive experiments of ROHMANN and NAGANO, saccharose 

 is absorbed more quickly than maltose. NAGANO 5 contends that the 

 pentoses are absorbed more slowly than hexoses. 



1 Mem. de 1'acad. roy. de medic, de Belg., 18. 



2 Voit and Lusk, Zeitschr. f. Biologic, 28; Rohmann and Nagano, Pfl tiger's Arch., 

 95, which contains the references to the literature. 



3 Otto, see Maly's Jahresber., 17; v. Mering, Arch. f. (Anat. u.) Physiol., 1877; 

 Moscati, Zeitschr. f. physiol. Chem., 50. 



4 Lannois and Lepine, Arch, de physiol. (3), 1; Rohmann, Pfluger's Arch., 41; see 

 also footnote 2. 



5 In regard to the literature on the absorption of sugars, see footnote 2. 



