286 
Notes. 
about by the living elements of the cell only, that the metabolized 
products would be identical with those of mere hydrolysis under 
enzyme action. 
Another point we had in view was, by observations on the * down- 
grade’ sugars, to determine if these afforded any evidence for or 
against the supposition of Sachs that the starch is in a continual and 
rapid state of flux at all times, and that the products of assimilation 
necessarily pass through the form of starch during their metabolism. 
It was also expected that some light would be thrown on the 
particular form in which the sugars wander from cell to cell in 
their passage out of the leaf into the stem, and on the nature of 
the sugars which contribute the most readily to the processes of 
respiration and new cell-growth. 
The only sugars which we have been able to find in the leaves of 
Tropaeolum are cane-sugar , dextrose , levulose , and maltose . No 
pentoses are present, or at most but mere traces. 
The total amount of the sugars, like that of starch, is subject 
to great variations, and the relative proportion which the sugars 
bear to each other also varies very much. 
We have in the full paper described in detail the methods we 
employed for isolating and quantitatively determining these sugars. 
As an example of the concordant results which can be obtained 
we give two determinations made upon the same sample of Tropaeolum- 
leaves. 
(B) 
(A) 
per cent. 
per cent. 
Cane-sugar 
3’ 2 4 
3*39 
Dextrose ) 
f 2-41 ) 
Levulose / 
4.69 
( 2.18/ 
Maltose . 
0-76 
o-6i 
Total sugars per cent. 
8-69 
8-59 
We have obtained a considerable amount of information from 
the systematic examination of the sugars and starch contained in 
leaves which have been placed under determinate conditions of 
illumination, both when still attached to the plant and after separation 
from it. We give one or two examples of these analyses. 
The following were the results obtained by an examination of 
leaves separated from the plant, A. at 9 a.m., and B. at 4 p.m. of 
a summer’s day - 
