1821.] the Nervous System on Animal Ileal. 39 



Comparing the average deduced from the first part of the 

 second, third, and fourth experiments, viz. 



Section of the brain 2*93° 



Violent commotion 2 - l 7 



Opium 2*25 



Average 2*45 



We see very different experiments affording nearly the same- 

 result. It was then natural to deduce the existence of a general 

 cause independent of the form of the experiments, and which, 

 in these three instances, had acted in an entirely similar manner. 

 Now the circumstance common to these three experiments 

 being the more or less complete abolition of the functions of the 

 brain, it was natural to enquire if it was not in the organs placed 

 under the immediate influence of the brain, that the real cause of 

 the diminution of animal heat would be found. Two queries to 

 resolve presented themselves : the one, to inquire whether the 

 refrigeration did not depend on the cessation of the influence of 

 the par vagum ; the other, whether this same effect did not 

 originate from the paralysis of spinal marrow. I am to detail 

 the results of these two series of experiments, beginning with 

 those which relate to the par vagum. 



I. Section of the Par Vagum. 



Legallois concluded from his experiments, that after the sec- 

 tion of the par vagum the animal died from asphyxia, occa- 

 sioned by the infiltration of blood, or serum, into the substance 

 of the lungs. My own researches, though confirming the truth 

 of this observation in young rabbits (on which Legallois seems 

 to have principally operated) induce me to doubt this assertion 

 as to its generality. So far from dying from asphyxia, I found 

 arterial blood in the substance of the lungs of full grown dogs, 

 and sometimes in the aorta itself. The cause of death in such 

 animals is the progressive diminution of animal heat ; for life 

 ceases only when the refrigeration is great enough to produce 

 death necessarily, and independently of every other cause. 



Exj)er. 5. — A tube was introduced into the trachea to prevent 

 the dyspnea consequent to the section of the nerves. The two 

 pneumogastric nerves were cut. Death took place the 60th hour 

 at 207° During the 36 hours, immediately consecutive to the 

 operation, numerous oscillations of the animal heat were ob- 

 served between 36° and 38-6°. 



In three sections of the par vagum, the average refrigeration 

 per hour was for the first part of the experiments : 



