THE STRUCTURE AND PROPERTIES OF PROTOPLASM. 57 



11. What effect is produced upon Protoplasm, as manifested in 

 its rate of movement, by electrical currents? 



Answer by Experiment 3. 



EXPERIMENT 3. To determine this, it is necessary to apply to the 

 living protoplast electrical currents which may be controlled in 

 strength and duration; this can be done by use of a simple electrical 

 slide in circuit with one or more battery-cells and a circuit-closer, 

 shown in Fig. 9. For induction-currents a small coil is to be intro- 

 duced. 



Place a tip-cell of Nitella upon the electrical slide, and test the 

 effect upon the movement in its cytoplasm of (a) a single cell, () 

 two and (<r) three cells, each applied (i) instantaneously, (2) for a 

 second, (3) two seconds, (4) three, (5) five, (6) ten seconds, and if 

 necessary longer. 



(The ends of the piece of Nitella must be in contact with bits of tin 

 foil which are in contact witJi t/ie clips and wires. ) 

 Try also the effect of an induced current from an induction-coil. 



/! " \ 



s 



FIG. 9. ELECTRICAL STAGE AND BATTERY. 

 One-fourth the true size. 



Is it the continued action of the current which produces the 

 effect, or the making and breaking of the circuit? 



Since the plant is never exposed to this influence in nature, 

 the response cannot be adaptive. 



What then is the probable explanation of its behavior? 



