ELECTRICAL POLARITY IN OBELIA 



487 



for they are the averages of all the tests rather than the averages 

 of the later tests in each series, which, as explained above, are 

 the most significant, e.g., stem no. 3 A. In general, differences 

 between galvanometer deflections of 1 mm. on the scale proved 

 to be significant whenever the electrical resistance' of the stem 



TABLE 4 



Showing that treatment of the living stem with chloroform-saturated sea-water causes 

 the disappearance of the normal difference of potential in the stem. A, tests made 

 on living stems immediately after removal of branches. B, tests on the same stems 

 after treatment in chloroform-saturated sea-water 



remained approximately constant. The limit of error is therefore 

 to be judged to some extent from the conditions of the experi- 

 ment and nature of the results. 



All the stems were now placed in fresh sea-water. No re- 

 generation occurred, showing that loss of the normal P.D. in 

 the stem was associated with death of the li^^ng tissue. A few 

 experiments were carried out in which various concentrations of 

 ether were used. The results indicate that a definite decrease 



