ii THE THERMIC ECONOMY OF THE ORGANISM 83 



Wood made numerous experiments to determine the effects of 

 cerebral lesions upon the temperature. Eleven times he found 

 hypothermia, and fifteen times hyperthermia. He came to the 

 conclusion that the only cerebral centre which can act on thermo- 

 genesis without acting on the vasomotor centres and nerves is 

 situated , in" or close to the pons, and probably acts as a thermo- 

 inhibitory. centre on lower centres situated in the spinal cord. 

 He was unable to prove that injury or stimulation of the brain 

 necessarily caused a rise of temperature. This last fact was 

 proved for the first time by the experiments made simultaneously 

 by Richet and I. Ott in 1884 A prick given with a pin or 

 stiletto in the front part of the brain of a normal rabbit was 

 enough to send its temperature up 2 in less than an hour, with- 

 out the production of any other abnormal effect, such as contractions 

 or paralysis. If the prick be repeated next day in the same part 

 of the brain, the hyperthermia may reach 42*5 in fifty minutes. 

 Sometimes, but not invariably, this hyperthermia coincides with 

 an increased excitability of the brain ; the animal runs about, or 

 starts at the slightest sound. 



Aronsohn and Sachs (1884) tried to ascertain which parts of 

 the brain will cause hyperthermia when they are punctured ; they 

 found them to be the front portions of the corpora striata, and 

 regarded these parts as the seat of a special heat centre. Girard, 

 however, who made various researches (1888) of the same kind, 

 only accepted this conclusion with important reserves, and 

 summed up his work in the statement " qu'il n'est pas permis 

 d'admettre 1'existence dans 1'ence'phale des animaux a temperature 

 constante d'un centre thermique unique." : 



An experiment carried out by Corin and van Beneden on 

 pigeons in 1886 proves that the corpora striata cannot be regarded 

 as the seat of a specific heat centre, or as a means of heat regula- 

 tion. After the ablation of the cerebral hemispheres, the capacity 

 to regulate the temperature remains unaltered in these animals ; 

 the daily curve of temperature takes the same course as in normal 

 pigeons ; the calorimetric determinations give values but little lower 

 than in normal birds. Goltz in his famous brainless dog did not 

 find any complete loss of capacity to regulate the temperature, 

 though the animal lost more heat than usual (Vol. III. Chap. 

 IX. p. 507). 



The numerous researches made by Hale White (1890-91) on 

 rabbits led him to support the view taken by Aronsohn and 

 Sachs. He considers that a rise in temperature is caused especially 

 by puncture of the corpora striata, sometimes also by puncture 

 of the optic lobes. No marked change of temperature is caused 

 by pricking the anterior or posterior cerebral convolutions, the 



1 "That it is not permissible to admit the existence of a special heat centre in 

 the brain of warm-blooded animals." 



