THE CHEMISTRY OF THE ANIMAL BODY. 1007 



This decomposition probably does not take place in the stomach. Neither 

 does the intestinal juice cause this transformation. 1 Milk-sugar is probably 

 absorbed unchanged, and is not a glycogen-producer except indirectly in the 

 sense of sparing proteid dextrose which may become glycogen. 2 The contrary 

 view, i. e. that milk-sugar is converted into dextrose and galactose, is held by 

 Minkowski 3 and others. The question is not definitely settled. 



Isomaltose. This is the only disaccharide which has been synthetically 

 obtained, having been produced by boiling dextrose with hydrochloric acid. 

 It ferments with difficulty and forms an osazone which melts at 150-153. 

 It, with dextrin, is a product of the action of diastase and of the diastatic 

 enzymes found in saliva, pancreatic juice, intestinal juice, and blood upon 

 starch and glycogen. Through further action of the same ferments isomaltose 

 is converted into maltose. 



Maltose. Maltose (and dextrin) are the end-products of the action of 

 diastase on starch and glycogen, the process being one of hydrolysis : 



3C 6 H 10 5 + H 2 = CUH.OU + C 6 H 10 5 . 



Maltose. Dextrin. 



It is likewise a product of the diastatic action of ptyalin (saliva), amylopsin 

 (pancreatic juice), and of ferments in the intestinal juice and in the blood. 

 Maltose readily undergoes alcoholic fermentation and forms an osazone which 

 melts at 206. It is converted into dextrose by boiling with acids. Certain 

 ferments convert maltose (and dextrin) into dextrose (see Starch). 



CELLULOSE GKOUP, (C 6 H 10 O 5 ) n . 



Cellulose. This is a highly polymerized anhydride of dextrose, perhaps also of man- 

 nose. It forms the cell-wall in the plant. It undergoes putrefaction in the intestinal 

 canal, especially in herbivora (see p. 976), and owing to the production of fatty acids it may 

 have value as a food. In man only young and tender cellulose is digested, such as occurs 

 in lettuce and celery. The bulk of herbivorous fecal matter consists of cellulose. Cellulose 

 is only with difficulty attacked by acids and alkalies. Tunicin, found among the tunicates, 

 is identical with cellulose, so that the substance is not solely characteristic of the vegetable 

 kingdom. 



Starch, (Cgll^C^)^ This substance on boiling with dilute acids breaks 

 down by hydrolysis principally to dextrose. It is found in plants, and 

 may be manufactured by them from cane-sugar, dextrose, levulose, and from 

 other sugars. It forms a reserve food-stuff, being converted into sugar as the 

 plant requires it in winter, for example. Starch gives a blue color with 

 iodine. According to recent investigations 4 starch is said to be broken up by 

 diastase into five successive hydrolytic cleavage-products as follows : (1) Amylo- 

 dextrin (C^H^Oy,)^ a substance giving a deep-blue color with iodine. This 

 is next changed to (2) Erythrodextrin, (C^H^O^ + H 2 O, or (C 12 H 20 O 10 ) 17 . 



1 Pregl : Pftuger's Archiv, 1895, Bd. 61, p. 359. 2 C. Voit, Op. cit., p. 260 et seq. 



3 Archiv fiir exper. Pathologic und Pharmakoloffie, 1893, Bd. 31, p. 161 ; Kausch and Sociii, ibid., 

 1893, Bd. 31, p. 398. 



4 Lintner and Dull : Serichte der deutschen chemischen Gendlschaft, 1893, Bd. 26, p. 2533. 



