the voluntary muscles with the brain, 167 



have any other purpose to serve than merely to contract 

 under the impulse of the motor nerves. For if they have a 

 reflective influence, and if their condition is to be felt or 

 perceived, it v^ill presently appear that the motor nerves are 

 not suitable internuncii betwixt them and the sensorium. 



/ shall first enquire, if it be necessary to the governance of the 

 muscular frame, that there be a consciousness of the state or degree 

 of action of the muscles ^ That vv^e have a sense of the condi- 

 tion of the muscles, appears from this : that we feel the effects 

 of over exertion and weariness, and are excruciated by 

 spasms, and feel the irksomeness of continued position. We 

 possess a power of weighing in the hand: — what is this but 

 estimating the muscular force ? We are sensible of the most 

 minute changes of muscular exertion, by which we know the 

 position of the body and limbs, when there is no other means 

 of knowledge open to us. If a rope-dancer measures his 

 steps by the eye, yet on the other hand a blind man can 

 balance his, body. In standing, walking, and running, every 

 effort of the voluntary power, which gives motion to the 

 body, is directed by a sense of the condition of the muscles, 

 and without this sense we could not regulate their actions. 



If it were necessary to enlarge on this subject, it would be 

 easy to prove that the muscular exertions of the hand, the 

 eye, the ear, and the tongue, are felt and estimated when we 

 have perception through these organs of sense ; and that 

 without a sense of the actions of the muscular frame, a very 

 principal inlet to knowledge would be cut off! 



If it be granted, that there must be a sense of the condition 

 of the muscle, we have next to show that a motor nerve is 



