1915] OSTERHOUT—PERMEABILITY 251 
tinued by placing the material for ten minutes alternately in CaCl, 
and NaCl, with the results shown in table III and fig. 4. After 
80 minutes the material was placed in sea water, where it soon 
regained its normal resistance of roro ohms. Twenty hours later 
the resistance was found to be unaltered and the experiment was 
repeated. After 80 minutes of alternate exposure to CaCl, and 
NaCl, the material was placed in sea water, where it soon regained 
its normal resistance, which it maintained for three days, when the 
experiment was discontinued. 
TABLE II* 
ALTERATIONS IN ELECTRICAL RESISTANCE OF Laminaria saccharina EXPOSED FOR 
IO MINUTES ALTERNATELY TO CaCl, 0.278 AND NaCl 0.52M 
Day ri Day 2 
peu Solution Resistance oo Solution Resistance 
ie sairane eRe Ne aes vias eR ee FORGO Pay vans pelt eae Gi as I01Io 
ge ee CaCl, 1500 PC: Ser eee CaCl, 1490 
MS a cies a NaCl 880 Oe or NaCl 880 
nc WAR ss Cath 1470 Fon a gs CaCl, 1500 
GOL Bicoege% NaCl goo oe lage SS at NaCl goo 
SO ee Pune CaCl, 1500 Occ) es CaCl, 1460 . 
RE NN ee NaCl 860 OOn cua es NaCl goo 
Le Perea i CaCl, 1470 Be ras ee CaCl, 1480 
Be eS aCl 890 ee aCl 880 
TEP ei Sea water bo} fe) O§ic os asi s Sea water 19010 
BES ie yeas . ' SAR Pes ce baw s ee ev eee ode keer ee 
Control in sea water 990 
Control in sea water 990 
* All readings were taken at 18° C. 
The resistance of the apparatus was 240 ohms. The net resist- 
ance of the tissue at the start, therefore, was 1o10— 240= 770 ohms, 
and the net conductance 1+770=0.00130 mho. After the first 
exposure to CaCl, the net resistance was 1500—240=1260 ohms, 
and the net conductance was 1+1260=0.00079 mho. The loss in 
conductance was 0.0013—0.00079=0.00051 mbho, or 39.2 per 
cent. 
After the first exposure to NaCl the net resistance was 880— 
240=640 ohms, and the net conductance 1+640=0.00156 mho. 
