of the Eighth Pair of Nerves. 597 



from that of the par vagum ; and also the observations of Le 

 Gallois relative to the effect upon the glottis of dividing either 

 or both of these nerves, which ig that already quoted, of di- 

 minishing Its aperture, and thereby obstructing the free en- 

 trance and exit of the air into the lungs, so as to produce dif- 

 ficulty of breathing, congestion, the general disturbance of the 

 functions of respiration and digestion, and death. Majendie 

 adopts the opinions of Le Gallois, and difficult as the expla- 

 nation of the pheenomena may appear at first sight, he thinks 

 them readily explained, considering the manner in which the 

 recurrent nerves are distributed to the muscles of the larynx. 

 If, he says, the division of the nerves be made low down in the 

 neck, the muscles which dilate the glottis become paralyzed, 

 while the constrictor muscles which are supplied from the su- 

 perior laryngial retain their action, and close the glottis more 

 or less completely. In such cases as these, in which life is more 

 protracted than usual, he supposes the division to fail in bring- 

 ing on the closure of the glottis, and inducing the other phaj- 

 nomena gradually, instead of speedily, putting an end to life 

 by the train of symptoms before noticed, creating difficulty of 

 breathing, and a consequent failure of the proper oxygenation 

 of the blood. Majendie says nothing of his own immediate ex- 

 perience as to the effects upon the digestive organs ; but, as a 

 collateral circumstance, the assumed fact of the diminution of 

 the glottis, by dividing the par vagum, seems worthy of ob- 

 servation, especially as it does not appear to be very satisfac- 

 torily demonstrated. 



Amongst our own countrymen the experiments of Dr. Haigh- 

 ton, though not conducted with any reference to my present 

 objects, afford an interesting view of the effects upon animal 

 life resulting from a division of the eighth pair of nerves ; espe- 

 cially as his experiments were varied in the mode of performing 

 them from any hitherto noticed. He observed considerable un- 

 easiness about the organs of respiration and the stomach, with 

 trembling of the whole body, that lasted from the time of divid- 

 ing the nerves in the neck of a dog till its death, which is 

 one instance occurred in eight hours, in another in two days, 



Vol. X. X 



