On Some Criticisms of the Osazone Method. 239 
the presence of maltose, though other possibilities are not altogether 
excluded. 
“ If actual crystals are formed the osazone can be identified 
with less uncertainty, though here again it is necessary to bear in 
mind alternative interpretations.” 1 
In this connection the work of Daish 2 on the occurrence of 
maltase in plants is of interest. This enzyme was found to be 
present almost universally in starch-forming plants, and to be 
abundant in the leaves. Maltose, however, was not found by 
Davis, Daish and Sawyer 3 in the leaves or conducting systems of 
plants, and its absence was considered to be due to “. . . . the 
amount of maltase always being in relative excess in the cells 
where the starch degradation actually occurs, so that it is able to 
deal instantly with the whole of the maltose formed from the 
starch. The fact that maltose, unlike cane sugar, never occurs in 
the stalks or conducting vessels is probably due to the fact that 
maltase is an intracellular enzyme and apparently acts in close 
collaboration and in the immediate proximity of the ordinary dias¬ 
tase which first attacks the starch in the cells where this substance 
is stored.” 4 
There is considerable interest in the above suggestion, although 
some time may yet elapse before the distribution of intracellular 
enzymes within the cell can be determined with any degree of 
reliability. 
It can readily be understood that an excess of maltase within 
cells containing starch undergoing hydrolysis might prevent any 
accumulation of maltose. But it can scarcely be that maltose 
is completely absent from the cells at all times, for it must come 
into existence for the maltase to act upon it, and until it can be 
proved that the maltose is produced in actual contact with the 
maltase it is reasonable to suppose that this sugar persists in the 
cell, at least for the short time required for it to travel to the 
enzyme prior to hydrolysis. 
The ordinary equilibrium relations obtaining in enzyme actions 
would presumably make the complete destruction of maltose within 
the cell unlikely while any dextrose remained in the same cell. It 
is, however, quite conceivable that owing to the activity and 
abundance of the enzyme, although the total turnover of maltose 
1 l.c., p. 379. 
2 Daish, A. J., 1916. “The Distribution of Maltase in Plants.” Biochem. 
Journ., X, pp. 31-76. 
8 l.c., pp. 311, 313, 353, 354, 357, 358 etc. 
4 l.c., p. 358. 
