1915] OSTERHOUT—PERMEABILITY 321 
This experiment has a special interest as affording positive proof 
that the current passes through the protoplasm as well as through 
the intercellular substance,‘ for it is evident that the rise in resis- 
tance in these experiments can not be due to any cause other than 
a change in permeability of the protoplasm. The concentration 
of the ions of the sea water remains unchanged, and if they were 
able to penetrate as freely as they did before the addition of the 
1400 OHMS 
5 10 HOURS 
Fic. 4.—Curves of electrical resistance of live tissue (upper figure) and dead 
tissue eaten figure) of Laminaria saccharina in 1000 cc. sea water+10cc. CaCh 5 M 
(unbroken line in both figures) and of controls in sea water facet line in both figures). 
TABLE IVa 
ELECTRICAL RESISTANCE OF DEAD TISSUE OF Laminaria saccharina 
n sea water ITooocc. 
Time in hours Me Sock 5 M toce. In sea water 
° | 370 380 
$ | 340 380 
3 340 380 
14 340 380 
a. 5 340 380 
‘ 340 380 
All readings were taken at 18°C. 
CaCl, the resistance would not increase. It would, in fact, di- 
minish on account of the increased conductivity of the solution 
held in the intercellular substance, as is clearly shown by experi- 
ments on dead tissue. That the change in permeability is in the 
e frond may be a as a mass of intercellular substance in which the 
Seeiceleca: masses are imbedded 
