316 THE BODY AT WORK 



sensory impulses towards the seat of consciousness. This shows 

 itself in the apparent increased sensitiveness of the skin of 

 the area of the surface supplied by the posterior root which 

 joins the segment of the spinal cord into which the pain in- 

 fluence is also being poured. For example, afferent sympa- 

 thetic nerves from the cardiac end of the stomach join the sixth 

 and seventh thoracic spinal nerves. Other afferent fibres run 

 up the vagus to the medulla oblongata. When the cardiac 

 end of the stomach is diseased, pain is referred to the skin area 

 supplied by the sixth and seventh dorsal roots. The ordinary 

 inevitable stimuli acting upon this area cause pain. Experi- 

 mental stimuli which elsewhere would be felt as touch or 

 warmth are painful. The impulses to which they give rise pass 

 through pain-agitated segments of the spinal cord. The 

 vagus nerve carries its pain influence to the medulla oblongata. 

 Now, it happens that the sensory nerve of the face the fifth 

 spreads for a considerable distance up and down the axis of the 

 brain. The fifth nerve in consequence pours its sensory 

 impulses into a region which is pain-agitated by those fibres of 

 the vagus which come from the cardiac end of the stomach. 

 Hence disease of that organ gives rise also to an " illusion " of 

 pain pains and illusions of pain are philosophically indis- 

 tinguishable on the surface of the head. The viscera, having 

 no direct access to consciousness, appear by deputy. When the 

 stomach is distressed, it makes its appeal to the whole body 

 politic for considerate treatment through certain nerves which 

 have the privilege of appearing at Court. The message is mis- 

 read as coming from the front of the chest " heart-burn " 

 or from the shoulder, or from the scalp, or from the other 

 skin areas which these nerves serve. When the liver is 

 in trouble, consciousness, having no knowledge of its where- 

 abouts is it the business of hand and eye to explore another 

 man's liver, or incumbent upon the mind to accept their 

 findings ? infers that the cry comes from the shoulder. Nor 

 have the tissues beneath the root of the nail, or the muscle 

 of the shoulder, or the pulp of a tooth, any direct representa- 

 tion in consciousness ; but since the pain-condition in the 

 grey matter converts it into a microphone, messages from 

 neighbouring structures which otherwise would fail to arouse 

 attention, after traversing the pain-segments of the nervous 



