68 CHAP. VII. EFFECT OF ELECTRIC STIMULATION 



Table VIII. — Effect of Intensity and Duration of Electric 

 Stimulation on Growth (Crinum). 



Contractile Response of Pulvinated and of 



Growing Organs 



Very striking is the similarity between the contractile 

 response of the leaf of Mimosa and that of the growing 



organ. For the purpose of 

 comparison I first give the 

 record of Mimosa under 

 moderate electric stimula- 

 tion. The up-curve exhibits 

 the contractile movement, 

 the successive dots being 

 at intervals of a tenth of a 

 second ; the recovery is slow, 

 and the successive dots in 

 the down-curve are at inter- 

 vals of 10 seconds (fig. 31). 



Experiment 36. Contrac- 

 tile response of a growing 

 organ. — A very similar re- 

 sponse was obtained with 

 a growing bud of Crinum 

 under electric stimulation 

 of moderate intensity, the recorder employed giving 

 a magnification of 1000 times. In fig. 32 the normal 



Fig. 31, 



Contractile response of leaf 

 of Mimosa. 



Up-curve (successive dots at intervals 

 of o • I second) indicates responsive 

 contraction. Down-curve shows 

 recovery (successive dots at inter- 

 vals of 10 seconds). 



