32 LEfCTUllE 1. 



Brodie.* As the circulation of the blood will 

 continue in warm as well as in cold blooded 

 animals without the influence of the brain, 

 provided respiration be artificially kept up 

 in the former by means of a pair of bellows, 

 Mr. Brodie severed the connection of the 

 brain from the top of the medulla spinalis, 

 which in effect instantly kills the animal, 

 and thereby prevents further suffering in 

 the experiment, and then maintained ar- 

 tificial respiration, and consequent cir- 

 culation, for more than two hours. Yet 

 under these circumstances the body cooled 

 as rapidly and regularly as that of another 

 animal in whom respiration and circu- 

 lation ceased upon the division of the 

 medulla spinalis. This experiment shews 

 that the change produced by respiration 

 on the blood is not of itself alone sufficient 

 to maintain the ordinary temperature of ani- 

 mals. Chemical science has not yet explain- 

 ed how the intense heat and light are pro- 

 duced, which are occasioned by the transit 



* Philosophical Transactions, 1811. Cromian Lecture. 



