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for instance, to go from yoivr home to your place of employment ; your 

 mind is occupied by a train of thought, something has happened which 

 has interested you, or you are walking with a friend, and in earnest 

 conversation with him ; and your legs carry you on without any con- 

 sciousness on your part that you are moving them. You stop at a 

 certain point, the point at which you are accustomed to stop, and very 

 often you will be surprised to find that you are there. While your 

 mind has been intent upon something else, either the train of thought 

 which you were following out in your own mind, or upon what your 

 friend has been saying, your legs move on of themselves, just as your 

 heart beats, or as your muscles of breathing continue to act. But this 

 is an acquired habit ; this is what we call a " secondarily automatic " 

 action. Now, that phrase is not very difficult when you understand it. 

 By automatic we mean an action taking place of itself. I dare say 

 most of you have seen automata of one kind or another, such as chil- 

 dren's toys and more elaborate pieces of mechanism, which, being 

 wound up with a spring, and containing a complicated series of wheels 

 and levers, execute a variety of movements. In each of the Great 

 Exhibitions there have been very curious automata of this kind. We 

 speak, then, of the actions being " automatic," when we mean that they 

 take place of themselves, without any direction on our own parts ; such 

 as the act of sucking in the infant, the acts of respiration and swallow- 

 ing, and others which are entirely involuntary, and are of this purely 

 reflex character. Now, those are " primarily automatic," that is, origi- 

 nally automatic ; we are born with a tendency to execute them ; but 

 the actions of the class I am now speaking of are executed by the same 

 portion of the nervous system the spinal cord and are " secondarily 

 automatic," that is to say, we have to learn them, but, when once 

 learned, they come very much into the condition of the others, only we 

 have some power of will over them. We start ourselves in the morn- 

 ing by an act of the will ; we are determined to go to a particular place ; 

 and it may be that we are conscious of these movements over the whole 

 of our walk ; but, on the other hand, we may be utterly unconscious of 

 them, and continue to be so until either we have arrived at our jour- 

 ney's end or begin to feel fatigued. Now, when we begin to feel 

 fatigued, we are obliged to maintain the action by an effort of the will ; 

 we are no longer unconscious, and we are obliged to struggle against 

 the feeling of fatigue, to exert our muscles in order to continue the 

 action. 



Now, having set before you this reflex action of the Spinal Cord, 

 you will ask me perhaps what is the exciting cause of this succession of 

 actions hi walking. I believe it is the contact of the ground with the 

 foot at each movement. We put down the foot, that suggests as it 

 were to the spinal cord the next movement of the leg in advance, and 

 that foot comes down in its turn ; and so we follow with this regular 

 rhythmical succession of movements. 



