THE CARBOHYDRATES AND THEIR METABOLISM 235 



The osones are colorless liquids which act as strong reducing agents. 

 By reducing them the sugars may be obtained. Glucose, fructose and 

 mannose form the same osazone, and so, of course, the same osone. When 

 glucosone is reduced, d-fructose is obtained. These reactions may there- 

 fore be used for converting an aldose into a ketose. 



TABLE IV 

 MELTING POINTS 



OF HYDRAZONES 



OF OSAZONES 



Ghicosides 



A glucoside is a compound which, upon hydrolysis with acids, yields 

 glucose (or another sugar) and one or more other substances. A great va- 

 riety of substances occur in plants, and to a lesser extent in animals, com- 

 bined with a sugar (usually d-glucose). The general formula is 



/H 

 C R 



HOCH 



CH.OH 



in which R may represent an alcohol, acid, aldehyde, phenol or a large num- 

 ber of other substances. 



