486 



E. J. LUND 



that all but stem no. 3 show a definite P.D. in the same direction 

 as that in the pre%dous experiments. The question naturally 

 arises, why did not stem no. 3 show a more definite and larger 

 P.D.? Some light on this question will be given later. 



TABLE 3 



Showing that the electrical difference of potential in a living stem disappears after 

 the living tissue (coenosarc) in the stem has been removed mechanically and sea- 

 water substituted for it in the perisarc tube. A, tests on living stem with coenosarc. 

 B, tests on same stems after mechanical removal of coenosarc. Numbers at top of 

 table refer to main stems of five different colonies. The — sign indicates that the 

 apical end is electronegative to the basal end 



iVfter the tests in A were made, all the pieces were treated with 

 chloroform-saturated water for thirty minutes, then quickly 

 rinsed in fresh sea-water and tested again. The tests after this 

 chloroform treatment are given in B. It is clear that the P.D. 

 has practically entirely disappeared. The differences in stems 

 nos. 1 and 4 are small but definite. Retreatment of stems 1 and 

 4 obliterated all trace of P.D. The average differences between 

 the deflections as given in the table are somewhat misleading, 



