250 Mr. Shaw on the ' Sense ' of Muscular Action 



This sensibility to the exercise of the muscular frame is 

 independent of sight, or any of the other organs of the senses ; 

 it is altogether a distinct source of sensation to the mind. 

 If a person were blind, or completely isolated from all out- 

 ward objects of sense, he would still be sensible of the motions 

 of his arms, or of his body, or of his eyes ; and if a standard of 

 comparison could only be communicated to him, he would be 

 able to tell in which direction and to what extent he moved 

 them. Although it has been only lately recognized that a 

 * muscular sense ' exists in the body, yet it appears to be as 

 distinctly one as any of the five senses, smelling, seeing, 

 hearing, taste, or touch. Anatomy discloses to us that nerves 

 whose office it is to convey sensations merely, and which are 

 incapable of influencing the muscles to contract, are distributed 

 with profusion to all the voluntary muscles throughout the 

 body. These sensitive nerves of the muscles^ it has been con- 

 cluded by Sir Charles Bell, convey to the brain the conscious- 

 ness of the contraction of the muscles which have been pre- 

 viously excited through the proper nerves of motion. They 

 establish a communication, as it were, in a circle, between the 

 muscles and the sensorium, whose office it is to regulate the 

 extent of the action of the muscles ; and they carry to the 

 mind that knowledge of the condition of the muscles, without 

 which their actions could neither be controlled nor adjusted, 

 nor be under the guidance of volition. 



Let us observe what takes place during vision, and we shall 

 perceive how intimately this ' sense ' of the muscular actions 

 is connected with the question before us. When we look at 

 an object placed high above us, the first thing which we natu- 

 rally do is to throw back the head, to turn the face towards 

 the skies, to elevate the upper eyelids, and to raise the cornea 

 of both eyes upwards. Now these actions are not performed 

 without our knowledge. If we have to inspect an object which 

 is placed on one side, we may be obliged to wheel round be- 

 fore we can see it ; at all events it will be necessary to turn 

 the eyeball in the socket towards that side. If we have to 

 examine an object placed at our feet, there is first a corre- 

 sponding motion of the eyeball and of the head, or it may be 

 of the whole body, in order to be enabled to look downwards. 



