On the Diastase of Koji. 



317 



twenty-five minutes, till it was quite clear. It was then rapidly heated 

 to boiling, cooled, and diluted to 250 cub. centims. 



100 cub. centims. of this solution, .after filtration, contained 2*15 

 grins, of solid matter, and 0*63 grm. glucose, determined by weighing 

 the cupric oxide after ignition. The optical rotation in a 200 millims. 

 tube was 32*4 scale-divisions. As the koji solutions contained in 

 250 cubic centims. was 25 cub. centims. (that is, one-tenth of the 

 whole), we must deduct the weight of solid matter and glucose con»- 

 tained in 10 cub. centims. of the koji extract from the weights above 

 found in 100 cub. centims. of the liquid. The optical rotation must 

 likewise be diminished by one-tenth the amount caused by the koji 

 solution alone. We thus get — 



Solids in 100 cub. centims. 



formed from starch 2"15 — 0*146= 2'004 grms. 



Glucose (or its equivalent). . . . 0*63-0-101 = 0'529 „ 



Optical rotation 32*4 —0*8 =31*6 scale-divisions. 



From which the observed specific rotatory power — 



31-6x0-2 42 = 190O , 8 

 r 2 x 0-02004 



The percentage composition calculated from the cupric oxide re- 

 ducing power is 



Maltose 43-28 



Dextrin 56' 72 



100-00 



which requires p=187°'4, taking maltose =150°, and dextrin 216°. 

 The agreement between the observed and specific rotatory powers is 

 sufficiently close to show that maltose and dextrin are produced. It 

 may be remarked, in passing, that Brown and Heron's equation. 

 No. 4, requires maltose =41-3 per cent., and /a=188°7. 



5 grms. of starch were gelatinised, and, after cooling to 40° C, 

 mixed with 25 cub. centims. of the same koji extract, and kept at 

 that temperature for three-quarters of an hour. An additional 

 .25 cub. centims. of koji was then added, and the whole allowed to 

 remain at 40° C. for a quarter of an hour longer, then boiled and 

 diluted to 250 cub. centims. After filtration, the solution contained, 

 deduction having been made as before for the koji) — 



Solid matter 2 '035 grms. in 100 cub. centims. 



Glucose (or equivalent). . 0*8882 „ „ 



Optical rotation 28 - 5 scale-divisions. 



.'./> (obs.)=169°-5. 



