On the Diastase o/K6ji. 



329 



logues." Tlie industrial employment of fungi under consideration is 

 an illustration of this, for, although the organic matter of the rice is 

 not completely destroyed it is removed to some extent in the form of 

 carbonic acid, and the albuminoids, though not converted into am- 

 monia, are undoubtedly degraded, and brought into such a form that 

 they can be dissolved out in great measure by water. It is doubtless 

 to the presence of albuminoids in this form that Jcoji owes its re- 

 markable action upon gelatinised starch. 



IV. — Change which the Rice Grain Undergoes by the Growth 

 of the Fungus. 



What is the nature of the change which occurs in the conversion of 

 rice into Jcoji ? As the grains have been exposed for a period of four 

 or five hours to the vapour of boiling water, and further, as the 

 embryo has been completely removed, it cannot be of the nature of 

 germination. The use of the fungus-spores and the growth of the 

 mycelium indicate that the alteration in 3 , properties is connected with 

 the growth of the mould, and it is probably of a similar character to 

 that described by Brown and Heron, which takes place in a solution 

 of barley under the influence of the yeast cell. They say: "An 

 aqueous extract of barley, which is submitted for a few hours at a 

 temperature of 30° C. to the action of ordinary yeast has its power of 



transforming starch much increased by this treatment 



It is evident, that the growing yeast cell is capable of inducing certain 

 modifications in the albuminoids which, during the ordinary process 

 of germination, are brought about by the action of the living vegetable 

 cell itself."* 



In this case we may suppose that the yeast cell in absorbing nitro- 

 genous food, does so by attacking the insoluble albuminoids contained 

 in the barley, and having taken what it requires, leaves the rest behind 

 in a degraded state, in such a form that water easily dissolves it. In 

 the formation of Icdji, we may assume that something of the same sort 

 occurs, the growing fungus attacks the insoluble albuminoids of the 

 rice, and in proportion as they are brought in bo a soluble state, so does 

 the diastatic property of the rice increase. The principal aliment of 

 the fungus is, doubtless, the starch granule, and this will be found to 

 be the case on examining the grain microscopically. The outer layers 

 of the Jcoji grain are loose ; the mycelium penetrates between the cells 

 everywhere, but in the centre the cells are horny, and no starch 

 granules are to be distinguished. 



The chemical change which takes place may be seen by comparing 

 the analysis of rice with that of Jcoji. The rice, before the removal 

 of the thin skin, has been examined by a number of chemists, and as 



* "Journal of the Chemical Society," Trans., p. 653, 1879. 



