30 ON THE INFLUENCE 



longer by means of artificial breathing, when the 

 thermometer had fallen to 76. The carbonic 

 acid evolved during these last 30 minutes 

 amounted to nearly 13 cubic inches. 



From the precautions with which these ex- 

 periments were made, there is reason to believe 

 that there can be no material error in their re- 

 sults. They appear to warrant the conclusion, 

 that in an animal in which the brain has ceased 

 to exercise its functions, although respiration 

 continues to be performed, and the circulation 

 of the blood is kept up to the natural standard ; 

 although the usual changes in the sensible qua- 

 lities of the blood take place in the two capillary 

 systems, and the same quantity of carbonic acid 

 is formed as under ordinary circumstances, no 

 heat is generated, and that (in consequence of the 

 cold air thrown into the lungs) the animal cools 

 even more rapidly than one which is actually dead. 



It is a circumstance deserving of notice, that 

 so large a quantity of air should be consumed 

 by the blood passing through the lungs, when 

 the functions of the brain, and those of the 

 organs dependent on it, are suspended. Per- 

 haps it is not unreasonable to suppose, that by 

 pursuing this line of investigation, we may be 

 enabled to arrive at some more precise knowledge 

 respecting the nature of respiration, and the pur- 

 poses which it answers in the animal economy. 

 It would however be foreign to the plan of the 

 present communication, to enter into any spe- 

 culations on this subject, and I shall therefore 



