author's abstract of this paper issued 

 by the bibliographic service, october 23 



EXPERIMENTAL CONTROL OF ORGANIC POLARITY 

 BY THE ELECTRIC CURRENT 



II. THE NORMAL ELECTRICAL POLARITY OF OBELIA. A PROOF OF 



ITS EXISTENCE 



E. J. LUND 



The Puget Sourid Marine Biological Laboratory and the Department of Ani7nal 

 Biology, University of Minnesota 



TWO FIGURES 



In the pre\dous paper (Lund, '21) it was shown that by passing 

 an electric current of proper density lengthwise through an 

 isolated internode from the stem of Obelia, it was possible to 

 inhibit polyp formation on the end turned toward the cathode, 

 while under these same conditions of current density a normal 

 pol^-p formed on the end of the internode which was turned 

 toward the anode. It was also shown that in order to inhibit 

 regeneration of polyps on apical internodes, it was necessary to 

 use a higher-current density than that which was necessary for 

 inhibition of polyp formation in internodes from basal levels of 

 the stem. The final general conclusion drawn from the experi- 

 ments was, that since it was possible in this way to inhibit 

 selectively polyp formation, the electromotive force applied from 

 an external source probably acted upon some kind of system 

 in the regenerating internode which was electrical (ionic) in 

 its nature and which in all probability was closely associated 

 with the mechanism which determines the polarity of the re- 

 generating tissue. This conclusion did not rest alone upon the 

 evidence from the experiments reported in the preceding paper, 

 for several investigators have reported more or less convincing 

 evidence that differences of electrical potential occur in hydroid 

 stems of Tubularia, Pennaria, and Campanularia (see, e.g., 

 Mathews, '03). More attention seems to have been paid to 

 these normal continuously existing potential differences in plants 

 than in animals (Buff, '54; Kunkel, '81; Elfving, '82; Burdon- 

 Sanderson, '82, and especially Miiller-Hettlingen, '83). 



477 



