THE CHEMISTRY OF THE SUGARS 85 



The first alcohol which fulfils the definition given above 



CH 2 OH 



is glycol, , so named from its sweet taste, and 



CH 9 OH 



CH 2 OH 

 the corresponding sugar is glycol-aldehvde, | 



CHO 



The next member of the series of alcohols is glycerol or 

 ordinary glycerine, whose sweet taste is a matter of common 



CH 2 OH 



knowledge. The formula for glycerol is CHOH, from which 



CH 2 OH 



it is evident that two first products of oxidation can be 

 obtained, that is, the CH 2 OH group may oxidise to an aldehyde 



/H 

 group C or the CHOH to ^rCO, the characteristic 



^0 

 ketonic group, and thus we have the following relationship : 



CH 2 OH CH 9 OH CH 2 OH 



I I I 



CHOH CHOH CO 



I I I 



CH 2 OH CHO CH 2 OH 



Glycerol Glycerolaldehyde Di-oxy-acetone 



These last two substances are the first representatives of 

 two important groups of the mono-saccharoses, viz., the 

 aldoses and the kctoses, the former containing the aldehyde 



/" 



group C and the latter the ketonic group ^>C=0. 



P 



The sugars it will be noted end in ose, and according to the 



number of carbon atoms they are referred to as biose, triose, 



