i7o Mr, Bell on the nervous circle which connects 



in the roots of the fifth and seventh in the brain ; the loss of 

 function of the fifth nerve therefore interrupted the circle. 

 Here too the motor nerve of the eye-lid was perfect, and the 

 eye-lid readily acted under the influence of the will, but when 

 the eye-lid was touched or pricked it communicated no sen- 

 sation. Is this insensibility of a motor nerve owing to the 

 course of its influence being from the brain, and not towards 

 it ? When the nostril had lost its sensibility from an affection 

 of the fifth pair, we could not excite sneezing ; when the 

 tongue and cheek had lost sensibility, the morsel was per- 

 mitted to remain between the tongue and the cheek until it 

 was offensive, although the motions both of the tongue and 

 the cheek were perfect. All these phenomena correspond 

 with the experiments on animals. 



Now it appears the muscle has a nerve in addition to the 

 motor nerve, which being necessary to its perfect function, 

 equally deserves the name of muscular. This nerve however 

 has no direct power over the muscle, but circuitously through 

 the brain, and by exciting sensation it may become a cause 

 of action. 



Between the brain and the muscles there is a circle of nerves ; 

 one nerve conveys the influence from the brain to the muscle, 

 another gives the sense of the condition of the muscle to the brain. 

 If the circle be broken by the division of the motor nerve, 

 motion ceases ; if it be broken by the division of the other 

 nerve, there is no longer a sense of the condition of the 

 muscle, and therefore no regulation of its activity.* 



* Thus led to conclude that there is motion in a circle, we nevertheless cannot 

 adopt the hypothesis of circulating fluids. That a fluid does not proceed from the 

 brain, we may learn from this ; that on touching the end of a motor nerve which 



