394 



COMPARATIVE ELECTRO-PHYSIOLOGY 



continuous stimulation, exhibit alternations of phase, negative 

 and positive, or vice versa, constituting multi-phasic or 

 oscillatory response. On these considerations it is possible 

 to summarise the principal effects caused by light, as 

 follows : 



MECHANICAL EFFECTS OF LIGHT ON PULVINATED AND 

 GROWING ORGANS. 



