XXVII.] INTELLIGENCE. ' 3 



those motor actions which are accompanied by conscious- Gradation 

 ness, and are under the control of the will. The action conToious 

 of the eyelids in closing is sometimes voluntary, but is to con- 



p. r. T . 1 • . 1 , • scious and 



oltener performed spontaneously, without consciousness or rational 

 will. The motion of the eyeballs is voluntary. And, to ™°!^oi" . 



'' J > actions, lu 



complete the evidence of a perfect gi-adation between the tlie eye, 

 unconscious or involuntary actions, and the conscious or 

 voluntary ones, it is asserted that in some few men the iris 

 is capable of being opened and closed at will.^ We find 

 the same gradation between involuntary unconscious action 

 and voluntary conscious action in the digestive system and iu the 

 also. The actions of the stomach, muscular as well as !!,lf^^!r'' 

 chemical, are quite involuntary, and in a state of health 

 are unaccompanied by sensation. The action of the throat 

 in swallowing is involuntary, though accompanied by 

 sensation. The action of the mouth in chewing and swal- 

 lowing is mostly performed in obedience to sensation, 

 with little direction from the conscious will, though it is 

 capable of being controlled by the will. Finally, the action 

 of the hands in conveying food to the mouth is altogether 

 voluntary. 



In these cases of the motor actions of the eye and of the 

 digestive organs, each distinct action has its own separate 

 set of muscles. But this is not true of all motor actions. 

 Coughing and sneezing, for instance, are actions that have 

 a definite purpose — namely, the removal of obstructions 

 from the air-passages — but have no special muscles for 

 their performance. These, like the winking of the eyes, are Actions 

 performed in obedience to sensation, and are only in part '^^}^'^' 

 under the control of the will. sensation. 



"We thus see that there is a perfect gradation from those 

 motor actions which, like the action of the iris in opening 

 and closing, are neither conscious nor voluntary, but are 

 determined by vital intelligence, through those which are 

 determined by sensation with little control from the will, 

 to the purely conscious and voluntary ones." At one end 



^ Lewes's Physiology, vol. ii. p. 222. He also states that men have 

 heen ahle to stop the action of the heart at will for a moment. 



^ See the tabular statement of the organic functions, vol. i. p. 163. 



b2 



