402 
Mr. Bell's experiments on the structure 
The nerves of the animal frame are complex , in proportion to the 
variety of functions which the parts have to maintain. 
When we minutely and carefully examine the nerves of 
the human body, and compare them with those of other 
animals, a very singular coincidence is observed between the 
number of organs, the compound nature of their functions, and 
the number of nerves which are transmitted to them. No 
organ which possesses only one property, or endowment, has 
more than one nerve, however exquisite the sense or action 
may be ; but if two nerves, coming from different sources, are 
directed to one part, this is the sign of a double function per- 
formed by it. If a part, or organ, have many distinct nerves, 
we may be certain that, instead of having a mere accumulation 
of nervous power, it possesses distinct powers, or enters into 
different combinations, in proportion to the number of its 
nerves. The knowledge of this circumstance gives new 
interest to the investigation of this part of anatomy. 
Thus, in reviewing the comparative anatomy of the nerves 
of the mouth, we shall find, that in creatures which do not 
breathe, the mouth having only one function to perform, one 
nerve is sufficient. In certain animals where the face and 
nostrils have no complexity of relations, these parts have only 
a single nerve. If the throat has no complexity of organi- 
zation, it has no variety of nerves. But on the other hand, 
when the anatomist employs weeks to dissect and disentangle 
the nerves of the tongue, throat, and palate, in the human 
subject, he finds at length, that he has exhibited the branches 
of five different trunks of nerves ; and there is no clue to the 
labyrinth, until he considers the multiplied offices of the mouth 
