DISACCHARIDES AND POLYSACCHARIDES 229 



not into grape-sugar, but into fruit-sugar. However, a series 

 of special investigations conducted by Pfliiger, 23 with this 

 point in view and using glycogen from animals after a diet 

 rich in Isevulose, have failed to give the least foundation for 

 such assumption. The liver and the other organs as well 

 must be looked upon as capable of inverting the polarizing 

 properties of sugars introduced. 



Behavior of Disaccharides and Polysaccharides. The 

 facts concerning the disaccharides are fairly well known. 

 Cane-sugar and milk-sugar can be completely assimilated 

 only if they enter the blood from the intestine, that is, after 

 undergoing full fermentation cleavage. When introduced 

 parenterally they pass for the most part unchanged into the 

 urine. Nor are they found capable of forming glycogen when 

 directly perfused through the living, excised liver (vide sup., 

 p. 228). Maltose, however, does not follow the same rule, 

 as the blood and tissues contain "maltases," ferments 

 capable of splitting this disaccharide when introduced 

 parenterally into the circulation; for which reason it is 

 readily assimilable. (Because of the readiness with which 

 maltose undergoes cleavage into dextrose, Murschhausen's 

 statement 24 that this sugar produces much less glycogen 

 than grape-sugar, fruit-sugar and cane-sugar cannot well 

 be understood.) It is not to be understood that the normal 

 body has absolutely no power of splitting parenterally intro- 

 duced cane-sugar. Small amounts of this carbohydrate 

 (one or two grams per kilo) introduced subcutaneously or 

 intravenously into a dog or a cat (as Lafayette Mendell has 

 recently discovered) 25 are not entirely excreted in the urine. 

 Ernst Weinland 26 observed that when cane-sugar was in- 

 jected in large amounts subcutaneously into grown dogs it 

 was usually entirely excreted; but when solutions of this 

 same sugar were injected into young dogs in increasing 



28 E. Pfliiger, Pfliiger's Arch., 121, 559, 1908. 

 "Pfliiger's Arch., 139, 255, 1911. 



25 L. B. Mendel and J. S. Kleiner, Amer. Jour, of Physiol., 26, 396, 1910. 



26 E. Weinland, Zeitschr. f. Biol., 1ft, 279, 1906. 



