THE FURFUROIDS. 199 



the sugar free. As quercitrin it has been found in many plants, 

 e.g., in sumach, hops, tea-leaves, ash, the horse-chestnut. 

 C 21 H 20 O n + 2H 2 = C 6 H 14 G + C 15 H 10 7 . 



Quercitrin. Rhamnose. Quercetin. 



Many other glucoside-like bodies have been obtained from 

 plants, some yielding glucose as well as rhamnose. 



Ehamnose forms hard crystals, very soluble in water, has a 

 sweet taste, but leaves a bitter after-taste. It loses its water 

 of crystallization at about 105. By reduction it forms the 

 penta-hydric alcohol Rhamnite or Bhamnitol, C 6 H 14 5 , a sweet, 

 soluble substance. 



Ehamnose, like glucose, is coloured yellow by alkalies and 

 reduces copper salts. It is coloured violet-blue by sulphuric 

 acid and a-naphthol. 



The Furfuroids. By this name Cross and Bevan" refer to 

 the substances present in cereal straw, jute fibre, and other 

 vegetable products, which when subjected to acid hydrolysis 

 give furfuraldehyde. The term includes the pentoses and 

 pentosans proper, but also another group of bodies pentose 

 derivatives to which the authors just quoted ascribe the con- 

 stitution 



CH H / ^CH, 

 XX 



CH 2 



/\ 

 which is probably O O 



COH.CHOH.CHOH.CH.CH 2 



These bodies are capable of fermentation with yeast, yielding 

 alcohol ; in this respect they differ from the pentoses, which 

 are apparently incapable of true alcoholic fermentation, though 

 under certain conditions they appear to be assimilated by the 

 yeast plant and to be destroyed. 



It is probable that the pure pentoses and pentosans are not 

 digestible (Ebstein), while these " furfuroid " bodies of the 

 type just described appear to be so. t From these results 



* Jour. Chem. Soc. 1896, 804, 1604 ; 1897, 1001. 



t Cross, Bevan, and Smith, Jour. Chem. Soc. 1807, 1003 ; also Cross, Bevan, and 

 Remington, Jour. Soc. Chem. Ind. 1900. 



