I9I4.] CRILE— THE KINETIC SYSTEM. 271 



nalin caused a rise in blood-pressure, an increase in the force of car- 

 diac contraction, increase in respiration, and a characteristic adrenaHn 

 rise in the blood-pressure of both dogs. The rise was seen first in 

 the dog whose brain alone received adrenalin and about a minute 

 later in the dog whose body alone received adrenalin. Histologic 

 examinations of the brains of both dogs showed marked hyperchro- 

 matism in the brain receiving adrenalin, while the brain receiving no 

 adrenalin showed no change. Here is a clear-cut observation on the 

 action of adrenalin on the brain — and both the functional and the 

 histological tests showed that adrenalin causes increased brain action. 

 The significance of this affinity of the brain for adrenalin begins to 

 be seen when I call attention to the following striking facts : 



1. Adrenalin alone causes hyperchromatism followed by chroma- 

 tolysis, and in overdosage causes the destruction of some brain-cells. 



2. When the suprarenal glands are both excised and no other 

 factor is introduced, the Nissl substance progressively disappears 

 from the brain-cells until death. This far-reaching point will be 

 taken up later. 



Here our purpose is to discuss the cause of the brain-cell changes. 

 We have seen that in crossed brain and body circulation trauma 

 cause changes in the cells of the brain which is disconnected from 

 the traumatized body by its circulation, but which is connected with 

 the traumatized body by the nervous system. We have seen that 

 adrenalin causes activation of the body connected with its brain by 

 the nervous system, and histologic changes in the brain acted on 

 directly by the adrenalin, but we found no brain-cell changes in the 

 other brainthrough which the products of metabolism have circulated. 



In the foregoing we find direct evidence that the brain-cell 

 changes are not due to the products of metabolism. We shall now 

 present evidence to show that the brain-cell changes are " work " 

 changes. What work ? We postulate that it is the work by which the 

 energy stored in the brain-cells is converted into electricity or some 

 other form of transmissible energy which then activates certain glands 

 and muscles, thus converting latent energy into heat and motion. It 

 has chanced that certain other studies have given an analogous and 

 convincing proof of this postulate. In the electric fish a part of the 

 muscular mechanism is replaced by a specialized structure for storing 



