A STUDY IN MORBID AND NORMAL PHYSIOLOGY. 255 



is a definite poison circulating in the blood, the poison sometimes having been 

 formed in the system, sometimes having entered the organism from without. 



Bearing these facts in mind, the theory of a causation of fever Ijccomes, to my 

 mind at least, very plain. It is simply a state in which a depressing poison or a 

 depressing peripheral irritation acts upon the nervous system which regulates the 

 production and dissipation of animal heat; a system composed of diverse parts so 

 accustomed to act in unison continually in healtli, that they become as it were one 

 system and suffer in disease together. Owing to its depressed, benumbed state, the 

 inhibitory centre does not exert its normal influence upon the system, and conse- 

 quently tissue change goes on at a rate which results in the production of more heat 

 than normal, and an abnormal destruction and elimination of the materials of the 

 tissue. At the same time the vaso-motor and other heat dissipation centres are so 

 benvmibed that they are not called into action by tlieir normal stimulus (elevation 

 of the g(>ncral bodily temperature), and do not provide for the throwing oif the 

 animal heat until it becomes so excessive as to call into action by its excessive 

 stimulation even their depressed forces. Finally, in some cases of sudden and ex- 

 cessive fever, as in one form of the so-called cerebral rheumatism, the enormous 

 and almost instantaneous rise of temperature appears to be due to a complete 

 paralysis of the nervous centres presiding over heat production and dissipation. 



