78 



BOTANICAL GAZETTE 



[JANUARY 



o.oiM. 4 The resistance rose rapidly to 1170 ohms, where it 

 remained for 10 minutes , after which it began to fall. The results 

 are given in table I and fig. 1. 



TABLE I 



Electrical resistance of Laminar ia saccharina 



Time in minutes 



In KCN 0.01M in 

 sea water 



In sea water 



O 



1 140 

 1160 

 1160 

 IISO 



IOIO 



910 



810 



710 



1080 



IO 



O 



20 



O 



30 



1070 

 O 



IIO 



200 



O 



'ZOO 



O 



400 



IO70 





1200 OHMS 



1000 



All readings were taken at 14 C. or corrected to this temperature. 



The resistance of the apparatus was 250 ohms; hence the 

 resistance of the tissue (the net resistance) at the start was 11 40 



250=890 ohms. We may 

 put the permeability as equal 

 to the conductivity, or, for 

 convenience, as equal to the 

 conductance; hence the 

 permeability was 1 + 890 

 0.001124. The maximum 

 net resistance was 11 70 

 250=920 ohms, and the 

 permeability was 1^920 

 0.001087. Hence the loss of 

 permeability was (o . 001 1 24 

 o . 001087) -7-0.001124 = 3.3 

 per cent. 



Similar experiments were 

 made with other concentra- 

 tions from 0.002M up to 0.381M (solution of KCN without sea 

 water). The results were irregular, and it is not possible to say 



* This mixture had the conductivity of sea water. The sea water after the 

 addition of the KCN was slightly alkaline to litmus. The hydrogen ion concen- 

 tration of 0.01M KCN* in sea water was 1.4X10— *° as determined by the gas 

 chain. The alkalinity tends to make the rise of resistance less pronounced. 



5 HOURS 



Fig. 1 





