494 E. J. LUND 



fore is not identical with the current of injury in, for example, 

 muscle, nerve, and other tissues. 



4. The magnitude of the fall of potential varies in pieces of 

 stems from different colonies. It also varies along the length 

 of the stem of the same colony, being greatest in the apical 

 actively growing region. 



5. A limited number of experiments indicated that the direc- 

 tion of the fall of potential in basal regions of the stem may be 

 opposite to that in the apical region. 



6. The difference of electrical potential between apical and 

 basal ends of pieces of stem after twenty-four or forty-eight 

 hours of regeneration w^as less than the potential difference in 

 the same pieces immediately after isolation. A tentative explana- 

 tion of this result is given in the text. 



7. The general conclusion from the experiments is, that since 

 normally inherent differences of electrical potential occur in the 

 stem of Obelia and are associated with apical growth, then it 

 should be possible to inhibit or modify developmental processes 

 by appropriate apphcation of an E.M.F. of external origin. 

 This was shown to be possible in the previous paper. 



LITERATURE CITED 



Batliss, W. M. 1911 III. The osmotic pressure of electrolytically dissociated 



colloids. Proc. Roy. Soc. Lond., vol. 84 B, pp. 229-253. 

 Buff, H. 1854 Ueber die Electricitatserregung durchlebende Pflanzen. Anna- 



len d. Chem. u. Pharm., Bd. 89, S. 76-89. 

 Burdon-Sanderson 1882 On the electromotive properties of the leaf of 



Dionea in excited and unexcited states. Phil. Trans., vol. 173, pt. I, 



pp. 1-56. 

 Elfving, F. 1882 Ueber eine Wirkung des galvanischen Stromes auf wachsende 



Wurzeln. Bot. Zeit., Bd. 40, S. 257- 264. 

 KuNKEL, A. J. 1881 Electrische Untersuchungen an pflanzlichen und tierischen 



Gebilden. Pfliig. Arch., Bd. 25, S. ;342-379. 

 LtJND, E. J. 1921 I. Effects of the electric current on regenerating internodes 



of Obelia commissuralis. 

 Mathews, A. P. 1903 Electrical polarity in the hydroids. Am. Jour. Physiol., 



vol. 8, pp. 294-299. 

 Muller-Hettlingen, J. 1883 Ueber galvanische Erscheinungen an keimenden 



Samen. Pfliig. Arch., Bd. 31, S. 193-214. 



