270 CRILE— THE KINETIC SYSTEM. [April 22, 



the storage batteries of which had been partially discharged, and of 

 those the batteries of which had been completely discharged; the 

 brains of woodchucks in hibernation and after fighting; the brains 

 of humans who had died from anemia resulting from hemorrhage, 

 from acidosis, from eclampsia, from cancer, and from other chronic 

 diseases. We have studied also the brains of animals after the ex- 

 cision of the suprarenals, of the pancreas, and of the liver. 



In every instance the loss of vitality — that is, the loss of the nor- 

 mal power to convert potential into kinetic energy — was accom- 

 panied by physical changes in the brain-cells. The converse was also 

 true — that is, the brain-cells of animals with normal vital power 

 showed no histologic changes. The changes in the brain-cells were 

 identical whatever the cause. The crucial question then becomes : 

 Are these constant changes in the brain-cells the result of work done 

 by the brain-cells in running, in fighting, in emotion, in fever? In 

 other words, does the brain perform a definite role in the conversion 

 of latent energy into fever or into muscular action; or are the brain- 

 cell changes caused by the chemical products of metabolism? Hap- 

 pily this crucial question was definitely answered by the following 

 experiment : The circulations of two dogs were crossed in such a 

 manner that the circulation of the head of one dog was anastomosed 

 with the circulation of the body of another dog and vice versa. A 

 cord encircled the neck of each so firmly that the anastomosing circu- 

 lation was blocked. If the brain-cell changes were due to the meta- 

 bolic products, then when the body of dog " A " was injured, the brain 

 of dog " A " would be normal and the brain of dog " B " would show 

 changes. Our experiments showed brain-cell changes in the brain 

 of the dog injured and no changes in the brain of the uninjured dog. 



The injection of adrenalin causes striking brain-cell changes — 

 first, a hyperchromatism, then a chromatolysis. Now if adrenalin 

 caused these changes merely as a metabolic phenomenon and not as 

 a " work " phenomenon, then the injection of adrenalin into the caro- 

 tid artery of a crossed circulation dog would cause no change in its 

 circulation and its respiration, since the brain thus injected is in ex- 

 clusive vascular connection with the body of another dog. In our 

 experiment the blood-pressures of both dogs were recorded on a drum 

 when adrenalin was injected into the common carotid. The adre- 



