Notes . 
285 
bound up with the life of the cell. When however we review all the 
facts, and give due weight to ( 1 ) the constant and abundant occurrence 
of diastase in leaves, (2) to the apparent correlation of this diastase 
with the occurrence of starch, (3) to the remarkable periodicity of the 
rise and fall of diastase, and (4) to the correlation of this periodicity 
with the appearance and disappearance of starch ; we cannot possibly 
accept Wortmann s view that the dissolution of starch in the leaf is in 
no way conditioned by a starch-dissolving enzyme. 
In fact we believe that our experiments, when duly considered, will 
establish beyond all doubt the physiological importance of diastase as 
an active agent in the dissolution and translocation of starch, not only 
in leaves but also in the growing parts of all plants. 
It is manifest that if diastase plays such an important part in the 
breaking down the starch, it is a necessary corollary that maltose should 
be found amongst the sugars of a leaf from which the starch is dis- 
appearing. That such is actually the case is rendered evident from 
a review of the results we have recorded in the concluding part of our 
paper dealing with the sugars of the leaf. 
As there seemed to be every probability of the sugars of the foliage- 
leaves of different plants varying considerably we thought there would 
be a better chance of arriving at some conclusions as to the genetic 
relations of the various sugars to each other and to the starch, if we 
confined our attention to the leaves of a single species of plant. After 
several trials we selected Tropaeolum as the plant most suitable for 
experiment, especially as we had already subjected it to full examination 
in other directions. 
Our experiments were planned with a view to ascertain not only the 
nature of the leaf-sugars and the variations in amount and relative 
proportions at different times, but also in the hope that we should 
throw some light on the relation which each sugar bears to the primary 
assimilation-products on the one hand, and to the leaf-starch on the 
other. We hoped in fact to determine which are the true ‘ up-grade ’ 
sugars towards starch, and to see if there is any evidence of the exist- 
ence of ‘down-grade" sugars proceeding from the hydrolysis of starch, 
and its subsequent metabolism. 
It is manifest that the presence or absence of maltose must have 
a very important influence upon our ideas of the physiological 
mechanism involved in the dissolution of starch in the living cell, for 
it is scarcely probable, if the disappearance of the starch is brought 
U 2 
