170 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 bram 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 
