42 Analyses of a Series of' Papers, by Mr. C. Bell, 



panding these air-tubes) are as regularly in action as the leva- 

 tor and depressor muscles of the ribs." It is very evident 

 that, when an animal is in such a state, many muscles are com- 

 bined in the act of respiration, which are seated apart from 

 each other, and are otherwise capable of performing distinct 

 offices : it is therefore the object of this paper to show what 

 nerves the) are which effect this combination, and are conse- 

 quently to be known as respiratory nerves ; but before these 

 can allow of being enumerated, it is necessary to observe, 



1st, That the nerves of the animal frame are complex, in 

 proportion to the variety of functions which the parts have to 

 maintain. 



For, on minutely and carefully examining the nerves of the 

 human body and comparing 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 performed 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 dif- 

 ferent 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 find that in the creatures which do not 

 breathe, the mouth having one function only to perform, one* 

 nerve is sufficient. It is the same with the face, the nostrils, 

 and the throat, of those animals where no complexity of re- 

 lations or of organization exists, there being no variety of 

 nerves in such a case. But in dissecting the parts composing 

 the tongue, throat, and palate, of the human subject, five dif- 

 ferent trunks of nerves may be found corresponding with the 

 multiplied offices of the mouth in man, snch as respiration, 

 manducation, speech, taste and feeling. Surely the same 

 nerve cannot serve for the action of gnawing and feeding in 

 the lower animals of simple structure, and also for the govern- 

 ance of those complicated operations which interpret wants 

 and sentiments in man. 



2dly, That the nerves of all creatures may be divided into two 

 parts or systems ,• the one simple and uniform, the other complex 

 and irregular in proportion to the complexity of organization. 



The principle which is to guide us towards a knowledge of 



these 



