THE CONDITIONS OF ACTIVATION OF UNFERTI- 

 LIZED STARFISH EGGS BY THE 

 ELECTRIC CURRENT. 



RALPH S. LILLIE AND WARE CATTELL. 

 (University of Chicago and Marine Biological Laboratory.) 



While sensitivity to the electric current seems universal in 

 living matter, its degree varies greatly apparently in corre- 

 spondence with the wide variation in general irritability. It is 

 most highly developed in rapidly responding tissues such as 

 muscle and nerve; but it can be shown to exist in supposedly 

 insensitive cells like epidermal cells, which respond to electrical 

 stimulation by increase of conductivity. 1 Specialized sensory 

 receptors (retina, auditory or chemical senses) all respond to the 

 electric current as well as to their own appropriate forms of 

 stimulation. Electrical sensitivity thus appears to be the 

 primary form of sensitivity. 2 In general, as the work of Nernst 

 and his successors has shown, it is intimately connected with 

 polarizability, which is dependent on the presence of diffusion- 

 resisting or semipermeable partitions enclosing or pervading the 

 protoplasmic system. Evidently the electric current acts within 

 the living system by influencing the chemical reactions at its 

 polarizable surfaces, as in electrode action in general; in living 

 protoplasm the surfaces concerned are those of the protoplasmic 

 structures, and especially of the films delimiting or separating the 

 protoplasmic phases. 



The directive or stimulating action of the electric current on 

 growth has been demonstrated in a number of cases, although 

 much remains to be done in this field. The unfertilized egg-cell, 

 however, seems usually to be relatively insensitive to the current. 

 The earlier evidence of electrical parthenogenesis in the eggs of 

 marine animals is inconclusive. Schiicking claims to have acti- 

 vated starfish eggs by passing the current from two chromic acid 



1 Ebbecke, U., Arch. ges. PhysioL, 1922, CXCV., pp. 300, 324. 



2 For a fuller discussion cf. the recent volume of R. S. Lillie, "Protoplasmic Act!" 

 and Nervous Action," University of Chicago Press, I9 2 3. PP- 273 el seq. 



IOO 



