DECREASE OF PERMEABILITY AND ANTAGONISTIC 

 EFFECTS CAUSED BY BILE SALTS. 



By W. J. V. OSTERHOUT. 



[From the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication, December 31, 1918.) 



Agents which increase permeabihty have long been known but the 

 discovery of substances which have the opposite effect is compara- 

 tively recent.^ The number of such substances known at present 

 (especially organic substances) is very small and it is therefore of 

 interest to find that bile salts possess this property. 



The discovery that some substances decrease permeability while 

 others increase it led the writer to the idea that substances of one class 

 may antagonize those of the other.^ It was of interest to test this 

 idea by ascertaining whether sodium taurocholate can antagonize 

 NaCl (which produces only an increase of permeability). Some ex- 

 periments on this subject are described in the present paper. 



The experiments were made by determining the electrical conduc- 

 tivity of Laminaria^ in solutions to which sodium taurocholate was 

 added. 



In the first experiments the bile salt was dissolved in sea water. 

 The amounts added to 1,000 cc. of sea water varied from 0.8 to 1.5 

 gm. If the sodium taurocholate were pure, 1 gm. in 1,000 cc. would 

 make the concentration about 0.002 m, but as its purity is doubtful 

 the concentration cannot be accurately determined.* 



After dissolving the sodium taurocholate the sea water was restored 

 to the normal conductivity and made approximately neutral to litmus. 



1 Cf. Osterhout, W. J. V., Bot. Gaz., 1915, lix, 317, 364. 



2 Osterhout, W. J. V., Science, 1915, xH, 255. 



^ For the method see Osterhout, W. J. V., /. Biol. Cheni., 1918, xxxvi, 557. 

 ^ The salt used was the purest obtainable. 



405 



