in ELECTRICAL EXCITATION OF MUSCLE 301 



the axial ray lies completely bared at many points. The spindles 

 and spheres glide slowly upon the axial ray (which at the same 

 time is being withdrawn into the body), in a centripetal direction, 

 sometimes coalescing, and finally flowing entirely into the proto- 

 plasm of the cortical layer." If the excitation is strengthened, 

 or prolonged continuously, the fluid vacuoles of the cortical layer 

 begin to collapse, after the pseudopodia have been withdrawn, 

 from the excited spot (or may be from the entire body), because the 

 protoplasm which forms their walls shrinks more and more inwards. 

 This gives to the body an irregularly-bounded, lumpy surface. 

 Finally, with still stronger excitation, the protoplasm begins to 

 disintegrate into granules, by a gradual process beginning at the 

 surface, and progressing slowly inwards until the central mass is 

 involved, when unless the excitation is stopped the entire body 

 is destroyed. Short of such total disintegration it is possible for 

 the undestroyed remainder to reconstitute itself into a perfect, 

 though correspondingly diminished Actinosphserium (Verworn, 

 47). With sufficiently strong excitation the plasmatic bands 

 and threads of certain vegetable cells (Tradescantia) will comport 

 themselves like the pseudopodia of rhizopods. With weaker ex- 

 citation there may frequently be observed, as in the case of 

 independent amceboid protoplasm, a slowing and arrest of the 

 spontaneous streaming movements, followed by the formation of 

 varicosities, lumps, and so forth, upon strengthening the excitation. 

 Kiihne observed that these effects were localised to a restricted 

 portion in correspondence with localised excitation. If a large 

 cell of Tradescantia is arranged transversely to a pair of fine- 

 pointed electrodes lying close together, it is possible to send 

 currents of great density through a limited part of the cell. 

 With gradual approximation of the secondary to the primary 

 coil the movements of only a portion of the cell are arrested, and 

 a formation of swellings, lumps, and knots ensues, which may be 

 subsequently reinvolved in the stream of the intact protoplasm. 

 The circulating plasma of Vallisneria, Chara, Mtella, etc., when 

 submitted to electrical excitation, always exhibits a retardation 

 and subsequent arrest of the streaming movements. 



The phenomena exhibited by certain kinds of protoplasm, 

 when submitted to the action of the constant current, are of far 

 greater interest. The first observations in this direction are due 

 to Kiihne, who, as long ago as 1864, drew attention to the re- 



