1915] OSTERHOUT—PERMEABILITY 465 
At the beginning of the first experiment: the resistance was 
1350 ohms; from this we must substract the resistance of the 
apparatus (240 ohms) to get the resistance of the tissue itself or the 
net resistance. This was 1350—240=1110 ohms, and the net 
conductance 1+1110=0.000g01 mho. The net resistance at the 
Maximum was 2350—240= 2110 ohms, and the net conductance 
Was I+2110=0.000474 mho. We may regard the permeability 
as equal to the conductivity, or for convenience we may, in such a 
case as this, regard it as equal to the conductance. The loss in 
permeability therefore was 0.000901—0.000474=0.000427 mho 
or 47.4 per cent. 
TABLE I 
ELECTRICAL RESISTANCE OF Laminaria saccharina; TWO EXPERIMENTS 
Time in hours seat? Ys | - TS | In sea water 
ESD ORIG Hen amen Ue ue 1350 | 300 1400 
Cte a eye ee ee 2080 pa Ca Si aati Ory gresearee ih Caer SETA 
aay ea ee ee ee 2160 S750 ae ee a a 
Be erie. Siem ris hoo 2350 D750 EN ees 2 as 
BOON ia vas ka ¢ 2315 TOO Coes we rer ess 
Sider eae es 2030 1490 1400 
PO tea ae 1340 600 1370 
LEE Ce ne oe 880 400 | 1359 
ee Ee eS ES A EPO Se a as 890 
3. Ee mere Us Gameleey ars) VAN er CS cere san | (orc Cinstn hae oie es 
Sg ere CEE ERAT ESOC aaa Cees ee ES | Jp sere nie Sk vee 
MES ho oot he 0G ee ee es Sees Ce ee 
bs hg, Eau amr yh eeaae te FM ro a re enue oe ees Puan apo oe 
oe ae ie eke ee Bae ee ce Se ee Ne 890 
All readings were taken at 18° C. 
The net resistance at the beginning of the second experiment was 
880—250=630 ohms, and the net conductance was 1+630= 
©.00159 mho. The net resistance at the maximum was 1490— 
250= 1240 ohms, and the net conductance was 1+1240=0.00081 
mho. The loss in permeability therefore was 0.00159—0.00081 = 
0.00078 mho or 49.1 per cent. Similar results were obtained with 
La.Cl. It will be seen that the rise in resistance is much greater 
in La,(NO). and La,Cl, than in CaCl. 
It has been pointed out’ that the severest test of the ability of a 
salt to decrease permeability is to add the salt in solid form to the 
