1821.] the Nervous System on Animal Heat. 43 



Exper. 22.— (Death 10th hour at about 26°) — °-**' a ° = 1-58°. 



The difference between the average refrigeration in these 

 experiments, and in those in which the brain has been acted 

 upon, is easily accounted for by the imperfection of the process 

 employed, which acts on one of the great sympathetic nerves 



only. 



Being unable to destroy the action of all the branches of the 

 great sympathetic nerves by acting on these nerves directly, it 

 appeared to me possible to prevent this action from having 

 any effect by depriving them of the materials on which they 

 v/ork. With this intention I tied the thoracic aorta immediately 

 above its passage through the diaphragm, by means of an inci- 

 sion in the last intercostal space. By this operation the animal 

 was divided in two parts ; the one composed of the abdomen 

 and hind parts entirely dead ; the other comprising the thorax 

 and head perfectly alive. These two portions of the animal 

 cooled precisely with the same quickness, and what is worthy 

 of notice, the dead part has always remained in an average of 

 07°, or 08° higher than the living: one. The average re frige ra- 



11 OS 



tion has been : 



Exper. 23.— In the rectum = 3S "°°~ r f — = 2-40°. Death the 



x 2 h 5 



fifth hour. 



the fifth hour. 



Exper. 24. 

 second hour. 



In the oesophagus = .; '' =2-40°. Death 



Exper. 24.— In the rectum = S8 '^ h J ~ = 2-74°. Death the 



T *i i 3" -s ° - 34-0° _ „_„ _ . 



In the oesophagus = ; — = 2-67 . Death 



the second hour. 



By these experiments, we find the whole average refrigera- 

 tion furnished by the experiments in which the brain was acted 

 upon restored. They terminate, for this reason, the experi- 

 mental .part of this inquiry. The rest of this paper presents that 

 explanation which seems to me to be the most probable of the 

 influence of the section of the par vagum on animal heat. But 

 as this inquiry could be treated in an experimental manner, it 

 seems to me useless to relate in this extract the theory I offer 

 on this occasion. 



