EXISTENCE OF HEAT CENTERS AND HEAT NERVES. 865 



centers in check. When cut off by section this inhibitory influence 

 is removed and increase in heat production and body temperature 

 results. A -second important fact, brought out by Ott,* is that in- 

 jury to the corpus striatum causes a rise in heat production and 

 body temperature. This result has been confirmed by many other 

 investigators, making use especially of what is known as the " heat 

 puncture." In this experiment, made upon rabbits, a probe or 

 style is inserted into the brain so as to puncture the corpus stria- 

 tum. The result in the majority of cases is a rise of temperature 

 which may last for a long time, although the animal shows no par- 

 alysis and apparently no other effect from the operation. Accord- 

 ing to some observers, t the increased production of heat takes place 

 mainly in the liver, and is due to the oxidation of the glycogen. 

 According to others (Aronsohn), the increased production of heat 

 occurs mainly in the muscles. The fever produced by the "heat 

 puncture" seems to be due essentially to an irritation of the nerv- 

 ous system, and is an experimental demonstration of the possi- 

 bility of fever arising from lesions of the nerve centers. White and 

 others have described similar disturbances of heat production from 

 lesions of the optic thalamus. Heat centers have been located 

 also in the septum lucidum, in the cortex, the midbrain, pons, and 

 medulla, while Reichert places the primary heat-producing centers 

 (thermogenic centers), from which the hypothetical heat nerves 

 originate directly, in the spinal cord in the anterior horn of the gray 

 matter. J The great amount of experimental work done along 

 these lines has been inspired doubtless by the hope of discovering 

 a special heat-regulating nervous apparatus which if demonstrated 

 would enable us to explain the causation of fevers. In its most 

 elaborate form this hypothesis assumes the existence of primary 

 heat-producing (thermogenic) centers in the cord and brain from 

 which the calorific or heat nerves arise. These centers in turn are 

 controlled by regulating (thermotaxic) centers of an augmenting 

 and inhibitory character in the higher portions of the brain. By 

 reflex influences upon these latter centers the activity of the thermo- 

 genic centers may be increased or diminished and the production 

 of heat in the body controlled. While such an apparatus may 

 exist, it is nevertheless true that the evidence in favor of it so far 

 produced has failed to convince the majority of physiologists. The 

 existence of a special set of heat nerves, in fact, is still unproved. 

 Most physiologists, perhaps, believe that variations in heat pro- 



* Ott, " Journal of Nervous and Mental Diseases," 1884, 1887, 1888; 

 also "Brain," 1889. 



t Roily, " Deutsches Archiv f . klinische Medicin, " 78, 250, 1903. 



t See Reichert, " University Medical Magazine, " 5, 406, 1894 ; also Kemp, 

 "Therapeutical Gazette," 1889, pp. 86 and 155. 

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