98 BACTERIOLOGICAL AND ENZYME CHEMISTRY 



value rather less than half that of the original solution. It 

 has been concluded that the glucose molecules when in solution 

 exist both in an aldehyde form and in an oxide form, viz. : 



CHO 



CHOH 



CHOH 



CHOH 



CHOH 



CHOH 



CHOH 



CH 2 OH 



Aldehyde form 



CH 2 OH 



Oxide form 



It will be seen that in the oxide formula the terminal 

 carbon atom attached to the oxygen is asymmetric, and con- 

 sequently two different derivatives are possible. By acting 

 upon glucose with methyl alcohol in presence of hydrochloric 

 acid two methyl esters have been obtained, which are really 

 the simplest members of the glucosides, their formulae being as 

 follows : 



H C-OCH 3 



CHOH 



CHOH 



CHOH 



CH 3 0-C-H 



CHOH 



CH 2 OH 



-Methyl glucoside 



CH 2 OH 



/8 Methyl glucoside 



