246 BOTANICAL GAZETTE [MARCH 
‘sea water through the experiment, it was not due to the sodium 
chloride but to other causes. The results are shown in table I and 
fig. 2. 
TABLE I* 
Day aa ag pr le mero Recovery Control in sea water 
etiam in NaCl 
Reet ha es 1020 130 Complete 1030 
BG eee 1020 100 1030 
Beatie sa | 1020 IIo . 1030 
Bere ode 1020 140 . 1030 
Re Eeea oe | 1020 120 . 1030 
Dent cosets 1020 120 - 1030 
sei tel eae | 1020 x : 1030 
Soo ee 1020 130 . 1030 
Oo oes 1020 120 s 1030 
ee | 120 f 1020 
oie Open verses } 1000 110 # Io10 
Fhe o c. | 8o 100 . 1010 
1 ea ame ane! 960 110 % 979 
Ra aa 950 120 , goo 
ee 930 I . 95° 
* All readings were taken at 20° C. 
Electrolytes may also cause a reversible decrease in permeability. 
The simplest way of demonstrating this is by means of the following 
very striking experiment. The resistance of a cylinder of living 
tissue in sea water was found to be 750 ohms. It was tested an 
hour later and found to be the same. Sufficient lanthanum nitrate 
(8.7 gm. to 1000 cc. sea water) was then added in solid form to 
make its concentration’ in the sea water o.orM. After five min- 
utes the resistance rose to goo ohms. As the resistance of the 
apparatus was 250 ohms, the net resistance before the addition of 
lanthanum was 750—250=500 ohms, and the net conductance 
I+500=0.002 mho. After treatment with lanthanum nitrate, 
the net resistance was goo— 250= 650 ohms, and net conductance 
I+650=0.00154 mho, a loss of 23 per cent. 
7 The concentration was reduced by the precipitation of a small amount of Jan- 
thanum sulphate; this had practically no influence on the subsequent result, since the 
outcome is the same if we use in place of sea water a mixture of 1000 cc. N aClo.52M+ 
20 cc. CaCl 0. 278M, in which case no precipitate is formed. It should be noted that 
the addition of lanthanum chloride has the same effect as the addition of lanthanum 
nitrate. 
