THE WONDERS OF LIFE 



stimulus of light acts just as luiconsciously in this as the 

 coral that spreads out its crown of tentacles under the 

 same influence; and when the sensitive carnivorous 

 plant [dioncea or drosera) closes its leaves in order to 

 catch and destroy the insect sitting on them, it acts in 

 the same way as the sensitive actinia or coral when it 

 draws in its crown, of tentacles for the same object — in 

 both cases without consciousness ! We call these uncon- 

 scious movements "reflex actions." I have dealt some- 

 what fully with these reflex movements in the seventh 

 chapter of the Riddle, and must refer the reader thereto. 

 This elementary psychic function always depends on a 

 conjunction of sensation and movement (in the widest 

 sense). The movement that the stimulus provokes is 

 always preceded by a sensation of the influence exerted. 



Modern physiology makes desperate efforts to avoid 

 the use of the word "sensation" and substitute for it 

 "perception of stimulus." The chief blame for this 

 misleading expression is due to the arbitrary and un- 

 justified separation of psychology from physiology. The 

 latter is supposed to occupy itself with the material 

 phenomena and physical changes, leaving to psychology 

 the privilege of dealing with the higher mental phe- 

 nomena and metaphysical problems. As we reject this 

 distinction altogether on monistic principles, we cannot 

 consent to separate sensation from the perception of 

 stimuli — whether this sensation be accompanied with 

 consciousness or not. Moreover, modern physiology, in 

 spite of its desire to keep clear of psychology, sees itself 

 compelled in a thousand ways to use the words "sensa- 

 tion" and "sensitive," especially in the science of the 

 organs of sense. 



What we call sensation or perception of stimuli may 

 be regarded as a special form of the living force or 

 actual energy (Ostwald). Sensitiveness or irritability, 

 on the other hand, is a form of virtual or potential 



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