THE CHEMISTRY OF THE ANIMAL BODY. 565 



result is obtained by warming with 0.05 to 0.2 per cent, hydrochloric acid at 

 the temperature of the body. 1 This inversion, therefore, takes place in the 

 stomach. In the intestinal canal the inversion is accomplished through the 

 action of a ferment present in the intestinal juice. Subcutaneous injection 

 of cane-sugar results in its quantitative excretion through the urine j 2 but 

 fed per os, cane-sugar is converted into dextrose and levulose, which may be 

 burned in the body. 



Milk-sugar, or Lactose. — This is found in the milk and in the amniotic 

 fluid. It is probably manufactured from dextrose in the mammary glands, 

 for the blood does not contain it. It is always present in the urine during 

 the first days of lactation, but is not found there antepartum. 3 It readily 

 undergoes lactic fermentation, producing lactic acid, which then causes clotting 

 of the milk. This fermentation may take place in the intestinal tract. Boiling 

 with dilute apids splits up milk-sugar into galactose and dextrose. This decom- 

 position probably does not take place in the stomach. The intestinal juice 

 causes this transformation, especially in suckling animals, 4 and lactase of the 

 pancreatic juice will also split milk-sugar. 5 Milk-sugar injected subcutane- 

 ously in man is quantitatively eliminated through the kidney. 6 It must, 

 therefore, undergo inversion in the intestine into galactose and dextrose 

 before it can be burned. 



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°-15o°. 

 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 l0 O 5 + H 2 = Ci 2 H 22 O u + C 6 H J0 O 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). 



(Vj/lulose Group, (C 6 IT 10 O r ,) n . 



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

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



1 Ferris and Lusk : American Journal <>j Physiology, L898, vol. 1, p. "J77 

 » Voit, F. : Deutsehes Archiv fur klinische Medizin, 1897, !'.<! 58, 8. 523. 



3 Lemaire: Zeitsckriftfur p/u/siologische Chemie, 1896, Bd. 10, S. 44"J. 



4 Weinland : ZeiUchrift fur Biologic, 1899, Bd. 38, S. 16. 



5 Ibid., 1899, Bd. 38, S. 607. " \ oit, F. : hoc. cit. 



