A STUDY OF FEVER. , ST 



It is a matter of the gravest scientific interest to decide 

 exactly where this inhibitory heat centre is situated. I have not 

 yet had time to undertake a research upon this point, hut hope 

 soon to do so. The known facts of clinical medicine seem, 

 however, to indicate that in the optic thalami, or their neighbor- 

 hood, are the ganglia which control chemical changes. Thus, 

 lesions of the optic thalami, according to Bastian, produce a 

 rise of temperature in the paralyzed limb which amounts to 

 from one and a half to two degrees, and " persists for a long 

 time, it may be for many weeks." There is, of course, no 

 reason for believing that, in this case, the increase of tempera- 

 ture is due to a vaso-motor paralysis, because the vaso-motor 

 centre is far below the part affected. More than this, those who 

 would attribute all these changes in temperature to vaso-motor 

 paralj^sis are here between Scylla and Charybdis. The limb 

 of the unfortunate child is permanently icy cold, because in in- 

 fantile palsy there is vaso-motor paralysis, and the limb of the 

 unfortunate man is permanently burning hot, because in apo- 

 plexy of the optic thalamus there is vaso-motor palsy. I believe 

 it to be a matter of grave doubt whether pure vaso-motor 

 paralysis is ever followed by a permanent rise of temperature ; 

 the local fever which * occurs after section of the so-called 

 sj'rapathetic nerves being very probably due to these nerves 

 being composed of two sets of nerve fibres, tlie vaso-motor 

 and those which proceed from the chemical centres to the 

 periphery. 



If what has already been asserted in this .ecture be true, 

 namely, that the fall of temperature which is produced by gal- 

 vanization of a sensitive nerve is independent of the circulation, 

 and that there is a controlling chemical centre, it is a priori 

 exceedingly probable that the fall of temperature is induced by 

 an excitement of this centre, consequent upon irritation of the 

 afferent nerve, or, in other words, that the fall of animal heat 



