Notes. 
93 
merged aquatic plants, in order that salt-solution should penetrate the 
living cells rapidly. After some rough preliminary experiments on 
Vallisneria , I selected Elodea canadensis and Callitriche sp. 
Experiments with Elodea. 
The leaves were placed in 50 cc. of solutions A to L. varying 
therefore from o per cent, up to *24 per cent, acid oxalate of potassium. 
When first put in the leaves contained starch. The leaves of Calli- 
triche were only casually examined to see that there was in general 
the same distribution of starch. The following table represents under 
the general heading II, the amount of starch found in leaves kept 
darkened for 24, 72, and 96 hours, in solutions A to L. 
II. III. 
Strength of 
solution of acid 
potassic oxalate. 
Amount of sta 
24 hours. 
rch in leaf after darkening for 
72 hours. 1 96 hours. 
Amount of starch in leaves 
after several days’ illumina- 
tion. Examined sometimes 
between io a.rn. and i p.m. 
A O 
O 
O 
0 
Starch present. 
B -000065 
O 
O 
0 
99 
C -00025 
O 
O 
0 
99 
D -ooi 
O 
O 
0 
More starch than in 
C, B. 
Much starch : more 
than B, C, D. 
E -0025 
O 
0 
0 
O 
9 
Small amount 
O 
0 
39 9 5 
G -oi 
Small amount 
Minute 
amount 
If anything had less 
starch than before 
illumination. 
II -04 
? 
Considerable 
amount 
Considerable 
amount 
Considerable amount 
of starch. 
N 
6 
00 
Considerable 
amount 
K .16 
>1 
99 
>> 
>> > J 
L ® 24 
V 
V 
y> 
These observations show that acid potassic oxalate retards the 
process of the change of starch into sugar in the living leaf. 
It remained to be seen, if, under conditions of alternating light and 
darkness, an abnormal accumulation of starch could be induced, such 
as occurs when plants are cultivated in solutions devoid of calcium. 
To ascertain this I continued this second series of experiments, but 
placed the leaves, still lying in their respective solutions, in front of 
a window in the laboratory. They were allowed to remain thus for 
