COMPOSITION, AND PROPERTIES OF KOJI. 
17 
soluble ferment winch acts on cane sugar, maltose, dextrins, 
and gelatinized starch, converting the three latter finally into 
dextrose, the former into inverted sugar. With reference to 
one point only the conclusions drawn by Atkinson do not 
appear fully justified. When examining whether maltose 
is one of the products of the action of koji extract on starch 
paste, he resorted to an indirect method, proceeding in the 
following way 4 : 
In the koji extract as well as in the solution obtained after 
liquefaction of starch paste by the extract at 40° C. he deter¬ 
mined the contents of the fluids in solid matter by the 
specific gravity (using the divisor 3.8G), and also the specific 
rotatory power. Furthermore he determined, after sacchar¬ 
ification, the reducing action upon cupric solution, and 
calculated from the amount of cuprous oxide, and from 
the weight of the starchy products (determined by the 
specific gravity) the weights of maltose and dextrin, as¬ 
suming these to be the only products. “If no other substance 
is formed, the specific rotatory power of the solution calcu¬ 
lated from the percentages of maltose and dextrin present will 
agree with the specific rotatory power of the solution actually 
observed. If they do agree the solution must contain the 
bodies assumed to be present, because if others were there, the 
specific rotatory powers would differ from one another.” 
Many of the assumptions involved in this method invite 
objection. The determination of the starchy products in 
solutions by the specific gravity is not reliable, as koji extracts 
(100 grms. of koji for 1 litre of water) contain up to 27% of 
nitrogenous bodies in their dry matter.—The koji extract 
itself alters upon being heated to 40°C ; its rotatory power 
before and after the action on starch paste is consequently 
not the same, and ought to have been separately ascertained. 
—The specific rotatory power of dextrin assumed by Atkinson 
to be 21G for white light cannot be expressed by a constant 
* L. c. p. 25. 
