314 Broughton on the Eighth Pair of Nerves. 



afforded no immedia.te intermission of this difficulty in respiring. 

 The symptoms went off for a time, but returned during the day 

 at intervals with the same violence, and the pony died in a state 

 of exhaustion about seven hours after the division of the nerves. 



I subsequently performed the same experiment on a full 

 grown rabbit, which was attacked with slow respiration very 

 soon afterwards. The symptoms returned after having ap- 

 parently subsided, and the animal was found dead in the morn- 

 ing after the operation. In neither of these cases was there 

 any demonstration of relief from an excision of the trachea, nor 

 any prolongation of life beyond the usual periods. I have been 

 informed by Mr. Brodie, that he also has tried the effects of 

 making an artificial opening in the trachea with no better 

 success. 



I am inclined to think, that the most probable mode of ac- 

 counting for the retardation and suspension of symptoms which 

 have been noticed, is the various degrees of susceptibility in 

 different animals and at different periods of life; and that when 

 the symptoms are not immediately apparent, or having come on 

 go off again, the nervous influence supplied before the division 

 of the nerves has been sufficient to avert for a time the conse- 

 quences of its farther supply being cut off, or to overcome the 

 immediate shock which some animals experience, and allow of 

 an interval of natural respiration and a due circulation of blood 

 to be carried on. 



Peculiar states of the constitution, and disease, as well as age 

 ^c, no doubt, have also their share in modifying the manner 

 in which the division of the par vagum affects different animals ; 

 and hence it appears to be presumable that this inquiry into the 

 influence of the eighth pair of nerves over the organs of respira- 

 tion and digestion, hitherto conducted for objects solely physio- 

 logical, may, if properly pursued, open to medical practice a 

 field of pathological investigation, calculated to throw consider- 

 able light on some affections of the thoracic and abdominal 

 viscera, at present remotely and imperfectly understood. 



London, October, 1820. 



