374 Heat Regulation and Death Temperatures. [Apr. 4, 



Whatever effect the fever-producing agent has upon the controlling 

 power of the higher thermogenetic centre, it will probably act in a 

 similar manner upon the thermolytic centre. If this should be the 

 case, paralysis or weakening of the functions of these two centres 

 would result in a much higher elevation of temperature than if the 

 thermogenetic controlling centre in the brain alone were affected. 



The following diagram shows the hypothetical relationship of the 

 different nerve centres which take part in the regulation of the bodily 

 temperature. The afferent path from the surface to the vaso-motor 

 centre has been left out for the sake of clearness. 



If A or B be paralysed or weakened, there is a tendency to pyrexia ; 

 if A and B be paralysed or weakened, there is a tendency to hyper- 

 pyrexia ; if C or D be paralysed or weakened, there is a tendency to a 

 fall of temperature. 



If A or B be stimulated, there is a tendency to a fall of temperature ; 

 if A and B be stimulated, there is likely to be an extreme fall of tem- 

 perature ; if C or D be stimulated, there is a tendency to pyrexia. 



From these considerations, and from the facts which have been 

 elicited by a careful study of the death variations of temperature, the 

 following theory for the causation of pyrexia seems to present itself. 

 Pyrexia is due to two factors, to an augmented production of heat 

 owing to the activity of the thermogenetic centres in the spinal cord 

 being no longer perfectly controlled by the higher centre in the brain, 

 and to a diminished loss of heat owing to the weakening of the 

 functions of the thermolytic centre ; the power of the two higher 

 centres being weakened or paralysed by the morbid products or 



