On the Diastase of Koji. 



observe that whilst cane-sugar yields invert sugar on hydration, its 

 isomer maltose yields only dextrose, a fact which indicates a difference 

 in the chemical constitution of the two bodies, arising probably from 

 the union of levulose and dextrose to form an ether in the case of 

 cane-sugar, whilst in the case of maltose the ether is formed of two 

 molecules of dextrose. 



Curve A. 

 Action of koji extract on maltose. 



Time in hours. 



(3.) Action of Koji Extract upon Dextrin. — A specimen of com- 

 mercial dextrin was used, probably prepared by the action of heat 

 upon starch, although its history was not known. 50 cub. centims. 

 of a solution of this dextrin containing 2' 78 grms. of solid matter, 

 and having a specific rotary power, p=174s°, were mixed with 50 

 cub. centims. of solution of koji, and the mixture heated for 

 hours at a temperature of 45° C. After heating, the solution con- 

 tained (deduction having been made for the koji added) 2'86 grms. 

 solid matter, and possessed a specific rotatory power, p = 92°. The 

 activity of the koji solution was destroyed, because when an additional 

 amount of koji solution was added, and the mixture heated for a 

 longer time, the specific rotatory power of the dextrin products further 

 diminished to 85°. 



This experiment, which has been confirmed by others, leaves no 

 doubt that dextrin gradually becomes hydrated under the influence of 

 the diastase of koji. 



(4.) Action of Koji Extract ujpon Gelatinised Starch. — 'When ex- 

 tract of koji is added to thick starch-paste at the ordinary temperature 

 of the air (i.e., from 15 to 20° C), in about ten minutes the paste 

 becomes very thin, but the solution does not become transparent. 

 When, however, the same experiment is made at any temperature 



