82 PHYSIOLOGY CHAP. 



action of tachypnoea, whereas the temperature of the second dog 

 will gradually rise from 40 to 43. . 



V. Our study of the mechanism regulating the temperature 

 leads to the general conclusion that it is a function of the nervous 

 system. Numerous experimental lesions of the spinal cord and 

 brain of the higher animals, and many lesions of these centres due 

 to accident or disease in man, have shown that hypothermia or 

 hyperthermia may be caused by a disturbance of the regulation 

 of temperature, produced respectively by destruction or stimulation 

 of these centres. 



The hypothermia following transverse section of the spinal 

 cord (C. Bernard and others) is readily explained as the effect of 

 the muscular paralysis, which lessens the production of heat, and 

 the paralysis of the blood-vessels, which increases the loss of heat. 



The cases of accidental or experimental injuries to the spinal 

 cord which produce hyperthermia are more obscure. Brodie 

 (1837) noticed that a fracture of the spinal cord in the neck 

 caused the temperature of the rectum to rise to 43'9 C. Billroth 

 (1870) found that the temperature rose to 42'2 after fracture of 

 the sixth cervical vertebra ; in a similar case Simon observed a 

 hyperthermia of 44 ; and Frerichs recorded a temperature of 43-8 

 in consequence of the fracture of the fifth and sixth cervical 

 vertebrae. 



Sometimes injuries to the cervical spinal cord cause hypothermia 

 instead of hyperthermia. Fischer found in two cases a lowering of 

 the temperature to 34 and 30 - 2 respectively. Breadburg (1885), 

 in a case of cervical paraplegia, noticed marked oscillations in the 

 temperature, which varied from 35 to 42. 



Physiological experiments were made with a view of confirming 

 these clinical observations. Fischer found that if instead of destruc- 

 tion or transverse section of the cervical portion of the spinal cord, 

 a simple puncture was made in it, the temperature of a dog rose 

 1'7. After crushing the cervical region of the cord, Naunyn and 

 Quincke observed that the temperature rose to 40 in five hours, 

 and to 42-3 in a day. 



The results of experiments on the medulla are not so con- 

 cordant. After transverse section of the bulb, Lewitsky (1869) 

 found that hypothermia constantly set in ; Bruck and Gunter 

 (1870), on the other hand, obtained in 23 cases eleven posi- 

 tive and twelve negative results. Schreiber (1874) noticed a 

 rise in temperature of 2, when he prevented the animal from 

 becoming cold by covering it with blankets. He considered that 

 the severance of the bulb or pons Varoli augments both the 

 production and the loss of heat, and that the latter exceeds the 

 former, and thus hypothermia is the result. Wood, on the contrary 

 (1880), found that injuries to the pons were almost always 

 followed by hyperthermia ; the production exceeded the loss of heat. 



