EFFECTS OF STIMULATION 



127 



indifferent region about i cm. below the region of growth. 

 On application of diffuse and moderate electric stimulation 

 of short duration, the response was an acceleration of growth 



Fig. 69. Effect of indirect and direct electric stimulation on 

 growth of Crinum, taken on a moving plate. 



Dotted arrow shows the indirect application of stimulus, with 

 consequent acceleration of growth (highly erect curve). 

 Direct application of stimulus at the second arrow induced 

 retardation of rate of growth which culminated in actual 

 contraction (down-curve). Successive dots are at intervals 

 of 5 seconds. (Magnification 2000 times.) 



which persisted for nearly a minute, after which there was a 

 resumption of the normal rate of growth. In this particular 

 case the interval of time between the application of stimulus 



Table XIV. — Accelerating Effect of Indirect Stimulation 



ON Growth (Crinum). 



Specimen 



Condition of experiment 



Rate of growth 



No. I. 



No. II. 



Normal 



After indirect stimulation 



0-2I // per second 

 0-26 n ,, 



Normal 



After indirect stimulation 



0-25 fi per second 

 0-30 fi ,, 



and the responsive acceleration of growth was 12 seconds. 

 The interval varies in different cases from i second to 

 20 seconds or more, depending on the intervening distance 

 between the point of application of stimulus and the re- 

 sponding region of growth. I give a record (fig. 69) obtained 



