278 CRILE— THE KINETIC SYSTEM. [April 22, 



interdependent? The following facts establish the answers to these 

 queries : 



1. The duration of life after excision of the liver is about the 

 same as after adrenalectomy — approximately eighteen hours. 



2. The amount of glycogen in the liver was diminished in all of 

 the experiments showing brain-suprarenal activity ; and when the 

 histologic changes were repaired, the normal amount of glycogen was 

 again found. 



3. In crossed circulation experiments changes were found in the 

 liver of the animal whose brain received the stimulus. 



From these premises we must consider that the brain, the supra- 

 renals, and the liver are mutually dependent on each other for the 

 conversion of latent into kinetic energy. Each is a vital organ — each 

 equally vital. It may be said that excision of the brain may ap- 

 parently cause death in less time than excision of the liver or supra- 

 renals, but this statement must be modified by our definition of death. 

 If all the brain of an animal be removed by decapitation, its body 

 may live on for at least eleven hours if its circulation be maintained 

 by transfusion. An animal may live for weeks or months after ex- 

 cision of the cerebral hemispheres and the cerebellum, while an over- 

 transfused animal may live many hours, for days, even after the 

 destruction of the medulla. It is possible even that the brain actually 

 is a less vital organ than either the suprarenals or the liver. 



In our research to discover whether any other organs should be 

 included with the brain, the suprarenals and the liver in this mutu- 

 ally interdependent relation, we hit upon an experiment which throws 

 light upon this problem. 



Groups of rabbits were gently kept awake for 100 hours by relays 

 of students, — an experiment which steadily withdrew energy but 

 caused not the slightest physical or emotional injury to any of them; 

 no drug, toxin, or other agent was given to them ; they were given 

 sufficient food and drink. In brief, the internal and external envi- 

 ronments of these animals were kept otherwise normal excepting for 

 the gentle stimuli which ensured continued wakefulness. This pro- 

 tracted insomnia gradually exhausted the animals completely, some 

 to the point of death even. Some of the survivors were killed im- 



