326 BOTANICAL GAZETTE [APRIL 
It will be noticed that while there is a very rapid and decided 
rise, the fall is much more rapid than in any of the previous experi- 
ments in which solid salts had been added to sea water. Neither 
of these effects can be attributed to acid, as the solution was neutral 
to litmus. After 18 hours the resistance was below that of the 
control and it continued to fall rapidly to the death point. Dead 
tissue showed no rise in resistance. 
Table VIII and fig. 8 show the results of experiments in which 
sufficient NiCl, +6H.O was added to the sea water to make the 
TABLE VIII 
ELECTRICAL RESISTANCE OF Laminaria saccharina 
n sea water 1000 cc 
Time in hours Nici SHO) I uy? gm In sea water 
° 940 890 
| 1000 nie 
3 1060 
I 1020 
2 I 
5 95° ae 
21 920 840 
44 760 600 
ae readings were taken at 18°C. 
concentration 0.005 M (1.19 gm. to 1ooocc. sea water). The re- 
sults are similar to those obtained with CoCl, +6H.O. Dead 
tissue showed no rise in resistance. 
Contrary to expectation the experiments with ZnSO, +7H.:0 
showed that it was less toxic than FeSO, +7H.O. The results 
are shown in table IX and fig. 9. 
TABLE IX 
ELECTRICAL RESISTANCE OF Laminaria saccharina 
sea water 1000 cc. 
Time in hours a8 Miypes P x ad gm. In sea water 
fe) 870 860 
Z 940 ak 
2 950 
I 
13 970 
3 920 Seyi 
19 830 720 
40 70o 640 
All readings were taken at 18°C. 
