292 GLYCASE. [CH. XVI 



200 C.C. of water and the mixture is then boiled and 

 filtered. The filtrate is tested for glucose. Some glucose 

 will always be found in this filtrate, but there is generally 

 so much more glucose formed from the solution which 

 contained maltose than in the control solution, that the 

 hydrolysis of maltose in the experiment is clearly demon- 

 strated. If however so much glucose is found in the 

 filtrate from the control solution that it is not obvious 

 that there is more glucose in the filtrate fi:om the maltose 

 solution, then determinations of the glucose must be made 

 in portions of each of the filtrates. 

 In this case determine 



(1) The original 'reducing power' of the maltose 

 solution. 



(2) The 'reducing power' of the same after the 

 action of the maize. 



(The increase of ' reducing power ' will be due partly 

 to the formation of glucose by hydrolysis of maltose and 

 partly to sugars formed from the maize itself.) 



(3) The reducing power of the solution obtained in 

 the control experiment. 



The amount of glucose in the filtrate from the actual 

 experiment can be calculated from the difference between 

 the values obtained for the ' reducing power ' in (2) and 

 (1) by the method explained on p. 267 ; and if the amount 

 of glucose found in (3) be subtracted from this the result 

 gives the amount of glucose formed from maltose in the 

 experiment. 



The determinations of ' reducing power ' may be made 



