galvanotropism 303 



normal rate of growth and K, retarded rate under the 

 action of the cathode. 



Fig. 11)7. Fig. Jim. 



FKt. 107. — Retardation of rate of growth under the actiou of cathode (Ki/soor), 

 Fig. 108. — Acceleration of rate of growth under anode (Kysoor). 



Effect of anode .- Kxjieriment 112. — li the cathode in- 

 duced a retardation, the anode might be expected to induce 

 an acceleration of growth. But in my Hrst experiment 

 on the action of anode, I could detect no perceptible 

 variation of rate of growth. In trying to account for this 

 failure, I found that the specimen employed for the experi- 

 ment had normally a very rapid rate of growth. It 

 appeared that an induced acceleration would be brought 

 out more conspicuously by choosing a specimen in which 

 the growth-rate was low, rather than in one in which it 

 was near its maximum. Acting on this idea, I took 

 another specimen of Kysoor in which the normal rate was 

 as slow as 0*10 fi per second. On applying the anode 



