58 THK \KHVUrS SVSTKM AND ITS COXSKKVATK >\ 



These statements serve to characterize reflexes in a 

 positive fashion. On the negative side \ve should empha- 

 si/e their essential independence of menial life. We 

 note the occurrence of many reflexes, hut our conscious- 

 ness is a matter of observation and not of initiation. 

 Tin- abrupt reflexes are "quicker than thought." while 

 those which are gradual in their development are usually 

 capable of pa-sing through all their stages without our 

 attending to them. When the will is enlisted at all if 

 we may trust our own impressions it is about as often 

 to restrain as to advance the process which we find taking 

 place. Nothing is harder for the average student than 

 to accept the view thai these acts witness only to struc- 

 ture and not to present intelligence. If the scientific 

 assertion is unwelcome, it may still be claimed that pa>t 

 intelligence i> registered in the structure which works so 

 .-smoothly. Holmes said that "habit is action in the 

 presenl from motives of the past"; the conception might 

 lie broadened to cover the field of the reflexes. But it 

 will be found unexpectedly difficult to defend even this 

 thesis. 



Voluntary Reactions. If a man presses an electric key 

 as soon as possible after hearing a sound, feeling a contact, 

 or seeing a spark, he is said to execute a voluntary reac- 

 tion, and the time which intervenes between the stimulus 

 and the response is called the reaction-time. It i- gener- 

 ally not less than 0.1'J second nor more than O.'J second. 

 Tlie values for different avenues of stimulation are 

 somewhat characteristic; for instance, the response to 



sound is more prompt than that to sight. The proce- 

 differs from an ordinary reflex in requiring attention to 

 insure the movement. The path of the nerve-impulses is 

 a long one. lying partly in the cerebrum and probably 

 including many synapses. 



When the lower eyelid receives an electric shock of 

 sullicient -nvngth there i- a wink which is quite involun- 

 tary. This is a reflex and it is :iccompli>hed within (K^ 

 iCond of the stimulus. With a somewhat weaker shock 



