MIND AND THE NERVOUS SYSTEM. 9 



made upon any one of the organs of tte senses without a higher 

 mental operation being performed. This is especially the case when 

 the perception is of such a character as to be irritative. Thus, if an 

 exceedingly bright light be allowed to impinge upon the retina, the 

 brows are corrugated, and, if it be still more intense, the eyelids are 

 closed so as to shut it out altogether ; if a very loud noise strikes upon 

 the tympanum, the head is turned so as to prevent the undulations of 

 the atmosphere reaching the ear in full force ; if the skin be irritated, 

 the part is, if possible, drawn away, and, if the irritation be so great 

 as to excite pain, the whole body is thrown into contortions and efforts 

 are made to escape. Some of these movements appear to be involun- 

 tary, and even to be performed in direct opposition to the will, and 

 then they are said to be reflex — that is, that they are the result of the 

 conversion of a sensation into a motor impulse without the accom- 

 panying action of any ganglion, the action of which is the evolution 

 of volitional force. 



Now, it is very true that some of the actions in question are appar- 

 ently altogether involuntary, and are thus true reflex movements, and 

 it is no diflicult matter to separate them from those other which are 

 clearly volitional, determinate, and performed with a definite purpose 

 in view. If, for instance, an irritative substance be applied to the 

 interior of the nostril, the action which we call sneezing is produced. 

 This consists of a spasmodic contraction of certain muscles by which 

 the air in the lungs is forcibly expelled through the nostrils. It is 

 automatic and preservative in character, the object being to get rid of 

 the offending substance. It is always performed in the same way, 

 the muscles brought into action are always the same, and it is spas- 

 modic, sudden, and without deliberation or judgment, so far as we can 

 determine from our own consciousness. Again, if the soles of the feet 

 are tickled, they are drawn away, although it is possible for the im- 

 pulse to remove them to be restrained by the exercise of the will, and, 

 indeed, some individuals can prevent sneezing by strong volitional 

 power evolved from the higher ganglia of the brain. But let us sup- 

 pose the case of a man with a disease of the upper part of the spinal 

 cord of such a character as to prevent its conveying volitional impulses 

 from the brain to the muscles of the lower limbs ; now let the soles of 

 the feet be tickled, and we shall find that they are drawn away, and 

 generally with very much more force than when the brain is allowed 

 to act. Such a movement is probably one of true reflex character ; it 

 is spasmodic and indeterminate, being more extensive than is neces- 

 sary. But let us go still further in our suppositions, and imagine that 

 in such a case the mere drawing away of the foot was not sufficient to 

 avoid the irritation, and that the individual deliberately lifted up the 

 other foot in the attempt to remove the offending object, and that this 

 action not proving adequate, he made two or three leaps in order to 

 escape. What would we call these movements ? Would they not be 



