CONTROL OF BODY TEMPERATURE AND FEVER 725 



elimination of chlorides is going on. Chlorides and water would there- 

 fore seem to behave in a similar fashion during fever. 



The Heat-regulating Center 



In all discussions on the regulation of body temperature and the 

 causes of fever, it is assumed that a heat-regulating or thermogenic 

 center exists somewhere in the brain. It is believed to be located 

 about the optic thalami or corpora striata, for it has been found in 

 rabbits that destruction of the brain anterior to this region does not 

 cause any change in body temperature, whereas destruction behind it- 

 is followed by an entire upset in the heat-regulating mechanism. Fur- 

 thermore, artificial puncture of this part of the brain causes marked 

 elevation in body temperature in rabbits (heat puncture). Most in- 

 teresting experiments have been recorded by Barbour, 56 who succeeded 

 in applying heat or cold locally in the 'region of the centers. By the 

 application of cold, increased muscular metabolism, on the one hand, 

 and diminished heat loss, on the other, were excited; and conversely, 

 when warmth was applied, an increased heat loss and a diminished heat 

 production were observed. Irritation of this region of the brain in man, 

 as after cerebral hemorrhage, is also accompanied by remarkable dis-. 

 turbances in heat regulation. It is believed by many that the essential 

 cause of infectious fever is an action on these centers by toxic substances 

 which develop in the blood. 



The centers may also be acted on by various drugs, some of which 

 excite them to increase the body temperature, others, to lower the tem- 

 perature when this has already been elevated. When solutions of sodium 

 chloride are injected intravenously or subcutaneously or even sometimes, 

 particularly in children, when administered by mouth, more or less fever 

 may result. This must be a specific action of the Na ion, for, if instead 

 of pure solutions of NaCl. solutions containing calcium and potassium 

 salts as well as those of sodium are injected, no fever is induced. This 

 fact, taken along with the close similarity between puncture diabetes 

 and heat puncture, lends support to the view that in its initial stages 

 experimental fever of this type is the result of an excessive breakdown 

 of glycogen in the liver. It must not be imagined, however, that persist- 

 ent fever can be attributed to such a cause, since the fever remains after 

 the glycogen has all been removed. Other chemical substances produc- 

 ing fever are caffeine, certain other purines, and particularly tetra-hydro- 

 naphthylamin. 



Belonging to this group of fevers must also be considered the im- 

 portant ones produced by the intravenous injection of certain forms of 

 protein, as those of egg white or those derived from the bodies of bac- 



