64 Arber . — On the Effect of Salts on the Assimilation 
Experiment XII. Artificial sea water without Mg S0 4 . 
Begun Jan. 19, 1900. 
Date. 
Days. 
Amoimt of Starch. 
Jan. 20 
1 
moderate 
Jan. 23 
4 
moderate 
Jan. 29 
TO 
1 
Begun Ja 
.n. 30, 1900. 
Feb. 14 
14 
maximum 
Mar. 1 
29 
maximum 
Experiment XIII. Artificial sea water without Ca S0 4 . 
Begun Jan. 19, 1900. 
Date. 
Days. 
A mount of Starch . 
Jan. 20 
1 
moderate 
Jan. 23 
4 
moderate 
Jan. 29 
10 
2 
Begun Jan. 30, 1900. 
Feb. 14 
14 
maximum 
Mar. 1 
29 
maximum 
The control in sea water was the same as in Experiment 
XI, and in nearly all cases the amount of starch formed 
during these experiments was fully equal to the control. 
Enteromorpha gave very similar results. In the first experi- 
ment sufficient magnesium was available from the Mg Cl 2 
present, and in both a sulphate was present. The only 
special point of interest was that the absence of calcium in 
1 Ulva was not estimated here, but Entero?norpha gave a moderate account. 
2 Enteromorpha moderate. 
