272 CRILE— THE KINETIC SYSTEM. [April 22. 



and discharging electricity. We found "work" changes in the 

 brain-cells of electric fish after all their electricity had been rapidly 

 discharged. We found further that electric fish could not discharge 

 their electricity when under anesthesia, and clinically we know that 

 under deep morphia narcosis, and under anesthesia, the production 

 both of heat and of muscular action is hindered. The action of mor- 

 phia in lessening fever production is probably the result of its de- 

 pressing influence on the brain-cells, because of which a diminished 

 amount of their potential energy is converted into electricity and a 

 diminished electric discharge from the brain to the muscles should 

 diminish heat production proportionally. We found by experiment 

 that under deep morphinization brain-cell changes due to toxins 

 could be largely prevented ; in human patients deep morphinization 

 diminishes the production of muscular action and of fever, and as 

 we shall see later conserves Hfe when it is threatened by acute in- 

 fections. The contribution of the brain-cells to the production of 

 heat is either the result of the direct conversion of their stored energy 

 into heat, or of the conversion of their latent energy into electricity 

 or a similar force, which in turn causes certain glands and muscles to 

 convert latent energy into heat. 



A further support to the postulate that the brain-cells contribute 

 to the production of fever by sending impulses to the muscles is 

 found in the efifect of muscular exertion, or of other forms of motor 

 stimulation in the presence of a fever-producing infection. Under 

 such circumstances muscular exertion causes additional fever, and 

 causes also added but identical changes in the brain-cells. Thyroid 

 extract and iodin have the same effect as muscular exertion and infec- 

 tion in the production of fever and the production of brain-cell 

 changes. All of this evidence is a strong argument in favor of the 

 theory that certain constituents of the brain-cells are consumed in 

 the work performed by the brain in the production of fever. 



That the stimulation of the brain-cells without gross activity of 

 the skeletal muscles and without infection can produce heat is shown 

 as follows : 



(a) Fever is produced when animals are subjected to fear with- 

 out any consequent exertion of the skeletal muscles. 



