276 Notes. 
(1) The absence of diastase from leaves, or its occurrence in very 
small quantities only. 
(2) That when diastase does occur it is of such a nature and 
so feeble in its action that, unlike the diastase of germinating grain, 
it cannot act upon the solid starch-granule. 
(3) That when the vital functions of the protoplasm are temporarily 
arrested by depriving the cell of oxygen then no disappearance of 
starch takes place, which ought not to be the case if starch-dissolution 
is dependent upon enzyme-action. 
As regards Wortmann’s first statement, that diastase rarely occurs 
in the leaf, our experiments are directly opposed to this. So far 
from leaves containing little or no diastase, we have not found a 
single case where diastase was not present in sufficient quantity to 
transform far more starch than the leaf can ever contain at one time ; 
in fact we shall see that diastase is frequently present to an extent 
sufficient to hydrolyze an amount of starch many times the total dry 
weight of the leaf itself. 
Wortmann attempted to determine the presence or absence of 
diastase by an examination of the clear filtrate obtained from a few 
hours’ maceration of the crushed leaves with water. 
The tenacity with which the protoplasm holds the enzyme, and the 
disturbing influence due to tannin, which frequently occurs in the leaf, 
render this method quite useless. It is only by previously drying the 
leaves, and using the dried tissue in actual contact with the starch- 
solution, that the full diastatic activity of the leaf can be appreciated. 
Although there seemed every probability that the products of 
hydrolysis of starch by leaf-diastase are identical with those yielded by 
the diastase of germinated grain, we were not justified in taking this 
for granted, especially as Vines 1 has recently stated that the sugar so 
produced is not dextro-rotatory. We have made very many experiments 
on this point, full details of which we have given in the paper. They 
prove, without room for doubt, that the products of starch-hydrolysis 
by leaf-diastase are identical with those brought about by malt-diastase. 
Moreover that the sugar so formed is really maltose we have proved 
by actually crystallizing it out, by the determination of its optical and 
reducing properties, and by the preparation of the maltoseazone with 
phenyl-hydrazin acetate. . 
1 Annals of Botany, vol. v. p. 409, 1891. 
