294 Bronghtoli on the hfluence 



minal viscera. The respiration, he observes, becomes labo*- 

 rious, and continues so incessantly till the animal dies, and he 

 refers the cause of death to the difficulty of breathing. Sub- 

 sequent French physiologists referred the cause of death to a 

 state of asphyxia following the division of the par vagum. 



Dupuytren says, that the asphyxia is produced by the at- 

 mospheric air not being capable of uniting with the blood of 

 the lungs, a phosnomenon which he states to belong to life ex- 

 clusively, and to depend on the influence of the brain. We 

 know, however, thatblood will mingle with atmospheric air out 

 of its vessels, and become converted to a bright crimson^ 

 Another objection to his doctrine is, that, were asphyxia the 

 direct cause of death, the animal ought to die as quickly as if 

 drowned or strangled. Blanville agrees with Haller in attri- 

 buting death to the impediment to the functions of digestion. 

 Proven9al attributed it to asphyxia, brought on by a diminu- 

 tion of oxygen gas, and a consequent deficient developement 

 of carbonic acid, from the interrupted breathing, by which the 

 temperature of the animal is reduced. In dogs he found the 

 lungs red and gorged with blood, but in pigs and rabbits no 

 such appearance was noticed. The asphyxia, therefore, he 

 concludes, does not take place immediately, but at a certain 

 point, and then increases till death. 



Such has been the vague and unsatisfactory information upon 

 this subject till Le Gallois engaged in these inquiries, to guide 

 him in his treatise on the principles of life. He performed the 

 experiment of dividing the eighth pair of nerves in numerous 

 animals, varying in age and species, so as to ascertain the in- 

 fluence which such variations held over the different symptoms 

 and phsenomena that follow the division of the par vagum. 



The result of his experiments is recorded with care and ac- 

 curacy, and the following circumstances form the leading fea- 

 tures of his experience which bear upon the present subject. 

 His chief care was to ascertain the immediate cause of the 

 death of animals after the division of the nerves ; and finding 

 with his predecessors that the heart, the lungs, and the stomach, 

 were all disordered by the operation, he endeavoured to make 



