336 PLANT AND ORGANIC CHEMISTRY 



sugar chain may be increased and a higher synthetic com- 

 pound formed. Upon the addition of prussic acid to sugar 

 compounds, the further processes of saponification and reduc- 

 tion are necessary before obtaining a higher sugar. By this 

 method it is possible to pass from sugars containing a few car- 

 bon atoms to sugars representing a higher synthetical series. 

 However, this method can only be used with sugar compounds 

 containing not less than 3 carbon atoms. Such compounds 

 have the power of forming lactones, and sugars of a higher 

 carbon percentage are obtained by reducing these lactones. 1 

 By the use of this method Fischer has obtained some of his 

 most brilliant achievements. 



The right, left, and inactive glucose and idose, which are 

 stereomers of glucose, have been obtained synthetically from 

 their corresponding acids. Idose is named from the symme- 

 trical form of its molecules, and is among the latest discovered 

 compounds of this group. The acids of these last two sugars 

 are isomeric with the sugar acids obtained by oxidizing glu- 

 cose and mannose. 



Two other sugars, which may be mentioned as belonging 

 to the hexoses, are galactose and talose. The right, left, and 

 inactive galactose have been obtained. The ^-galactose as 

 well as the ^-glucose may be derived from milk sugar by hy- 

 drolysis. The latter may also be obtained by the same means 

 from other carbohydrates. Galactose yields, on reduction, an 

 alcohol called dulcite. These sugars belong to the second divi- 

 sion of the hexose group, known as the dulcite group, and by 

 oxidation yield mucic acid; whereas the sugars of the mannite 

 division yield, on oxidation, saccharic acid. All these sugars 

 may be separated from their solutions, in a solid form, by 



1 The lactones are gamma hydroxy compounds, which, by the loss of 

 water, give an anhydride. 



CH 2 OH 



CH 3 

 JH, 



COOH 



Counting from the one above the bottom group, the carbons are known as 

 the alpha, beta, gamma, delta carbons, etc. 



