228 -^" Analyses of Books. [Sept." 



motor nerves entered the several muscles, they were joined by 

 branches of the nerves which came through the Gasserian gang- 

 lion, and which were sensitive nerves. 



" I found the same result on tracing motor nerves into the 

 orbit, and that the sensitive division of the fifth pair of nerves 

 was transmitted to the muscles of the eye, although these 

 muscles were supplied by the third, fourth, and sixth nerves. 



" A circumstance observed on minute dissection remained 

 unexplained, — when motor nerves are proceeding to several 

 muscles they form a plexus ; that is, an interlacement and 

 exchange of fibres takes place. 



'* The muscles have no connexion with each other, they are 

 combined by the nerves ; but these nerves, instead of passing 

 betwixt the muscles, interchange their fibres before their distri- 

 bution to them, and by this means combine the muscles into 

 classes. The question therefore may thus be stated : why are 

 nerves, whose office it is to convey sensation, profusely given to 

 muscles in addition to those motor nerves which are given to 

 excite their motions? and why do both classes of muscular 

 nerves form plexus ? 



" To solve this question, we must determine whether muscles 

 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 will 

 presently appear that the motor nerves are not suitable inter- 

 nuncii betwixt them and the sensorium. 



'* Ishalljirst inquire y if it be necessary to the governance of the 

 muscular frame J that there he a consciousness of the state or degree 

 of^ action (f the muscles? That we have a sense of the condition 

 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 know- 

 ledge 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 



