﻿iqi6] OSTERHOUT — PERMEABILITY 153 



This result is the more striking inasmuch as material of which 

 the resistance has fallen as much as 150 ohms in NaCl recovers 

 completely when placed in sea water, and may even undergo this 

 treatment daily for several days in succession without injury. 7 



TABLE V 



Electrical resistance of Laminaria saccharina 



850 



nOHMS 



The fall of resistance below the normal may be taken as a meas- 

 ure of the toxicity. The toxicity increases with the concentration, 

 and it should be noted that it is greatly decreased if the material 

 is allowed to stand in an open dish, 

 owing to the evaporation of the 9 *>0 n OHMS 

 ether. If the material be placed 

 in a closed jar, oxygen n 

 supplied. The other alte 



frequent renewal of the solution, is J 2 HOURS 



usually preferable. FK . 4 .-Curve showing the decrease 



A series of investigations on in pe rm eability (increase in electrical 

 Chloroform gave similar results, the resistance) of Laminaria saccharina 



chief difference being that chloro- ™^ ^J^^^^^^. 

 form is much more toxic, and that ^^^^TZwTtJd^ad 



the concentration necessary for resistance of a control in sea water. 



long continued decrease of perme- 

 ability is much lower, being about 0.05 per cent by volume, or 

 0.064 M. This is shown by table V and fig. 4, which are the 

 results of an experiment with a mixture containing 999.5 cc. sea 

 7 Science N.S. 36:350. 1012; Bot. Gaz. 59:242. 1915. 



