234 SIR CHARLES BELL ON THE ORIGIN AND COMPOUND FUNCTIONS 



Considering the nerve in this, perhaps its most important function, that is 

 operating upon the tubes or passages for the breath, dm-ing sleep and insensibility, 

 we have next to contemplate it, as combining the effort of the will in unison with 

 that of respiration. It is in this combined exercise that we have to be most grateful 

 for the effect, — the vibrations of the tubes modulated into articulate language, — 

 the performance at once of that function most necessary to existence, and that 

 faculty of speech essential to the developement of the powers of the mind as the 

 instrument of thought. 



Finally, the facial nerve is the source of expression. If the properties of 

 this nerve through any accident be lost, accidentally cut across, pressed on by a 

 tumour, or engaged in inflammation, the corresponding side of the face remains 

 motionless and blank. The cheeks and lips are blown out like a window-blind. 

 They have neither tension nor action. Expression, whether in laughter or in 

 tears, and all the intermediate conditions, continue to influence the other side of 

 the face, but with frightful distortions, puUing upon the side which has lost 

 power. 



There are instances recorded, now that the cause is understood, of entire 

 loss of expression on both sides of the face. A young woman, in whom the roots 

 of the nerve on both sides were involved in disease, exliibited the most distress- 

 ing consequences, — for whether she laughed or cried, the features were inunove- 

 able. She laughed under a mask, a sad thing to witness, a light heart behind a 

 face in the repose of death. 



There is an animation coincident with speech, and a reflection of the mind in 

 the human countenance, at all times. We have the full sense of tliis only from the 

 eflFects of this nerve being cut, for then the featm-es are completely fallen, more 

 divested of expression than a mask or a bust, for it is not the fixed state of a 

 statue which has meaning, but something worse than death. 



If this condition of total inaction continue, the plumpness of the face is lost, 

 and the skin becomes like a piece of parchment stretched over the bones. It is a 

 remarkable thing to see, in one sense, the life and sensibility of the parts remain- 

 ing, whilst there is a ruin of all which is a reflection of the mind. The muscles 

 of the jaws, however, remain as powerful and active as before, having theh energies 

 excited through the nerves of the other system. 



We now perceive the correspondence between the roots of the facial nerve 

 and the ofl&ces it has to perform in the face. We recognise its double roots, its 

 relation to two distinct columns in the performance of two distinct functions. 

 We perceive its Uvely subjection to the wiU, because of its relation to the motor 

 colvimn, whilst its origin in common with the eighth pair of nerves explains to 

 us how it is that the nostrils and lips move simultaneously with the other parts 

 engaged in the act of respiration ; in other words, how the vital actions through 



