THERMAL CORTICAL CENTRES. 705 



body. Horsley and Schafer observed only a temporary hemianesthesia, but they 

 found that an extensive lesion of the gyrus fornicatus was followed by hemianaes- 

 thesia, more or less marked and persistent. From their experiments, these observers 

 conclude that the limbic lobe " is largely, if not exclusively, concerned in the appreci- 

 ation of sensations, painful and tactile."] 



6. Munk is of opinion that the surface of the cerebrum in the region of the motor centres acts 

 at the same time as " sensory areas" (" Fiihlsphdre"), i.e., they serve as centres for the tactile 

 and muscular sensations and those of the innervation of the opposite side. He asserts that after 

 injury to these regions the corresponding functions are affected. 



According to Bechterew, the centres for the perception of tactile impressions, those of inner- 

 vation, of the muscular sense, and painful impressions are placed in the neighbourhood of 

 the motor areas (dog) ; the first immediately behind and external to the motor areas, the others 

 in the region close to the origin of the Sylvian fissure. [So far this agrees with the views of 

 Starr (p. 699).] 



Goltz, who first accurately described the disturbances of vision following upon injuries to the 

 cortex in dogs, is opposed to the view of sensory localisation. He believes that each eye is 

 connected with both hemispheres. He asserts that the disturbance of vision, after injury to 

 the brain, consists merely in a diminished colour- and space-sense. The recovery of the visual 

 perception of one eye after injury of one side of the cortex cerebri, he explains by supposing 

 that this injury merely causes a temporary inhibition of the visual activity in the opposite eye, 

 which disappears at a later period. Instead of psychical blindness and deafness he speaks of a 

 " cerebro-optical " and " cerebro-acoustical weakness." 



377. THERMAL CORTICAL CENTRES. Eulenberg and Landois discovered an area on 

 the cortex cerebri, whose stimulation produced an undoubted effect upon the temperature and 

 condition of the blood-vessels of the opposite extremities. This region (fig. 483, I, t) generally 

 embraces the area in which, at the same time, the motor centres for the flexors and rotators of 

 the fore limb (3), and for the, muscles of the hind limb (4) are placed. The areas for the anterior 

 and posterior limbs are placed apart, that for the anterior limb lies somewhat more anteriorly, 

 close to the lateral end of the crucial sulcus. Destruction of this region causes increase of the 

 temperature of the opposite extremities; the. temperature may vary considerably (1*5 to 2, 

 and even rising to 13 C). This result has been confirmed by Hitzig, Bechterew, Wood, and 

 others. This rise of the temperature is usually present for a considerable time after the injury, 

 although it may undergo variations. Sometimes it may last three months, in other cases 

 it gradually reaches the normal in two or three days. In well-marked cases, there is a dimin- 

 ution of the resistance of the wall of the femoral artery to pressure, and the pulse-curve 

 is not so high (Eeinke). Local electrical stimulation of the area causes a slight temporary 

 cooling of the opposite extremities, which may be detected by the thermo-electric method. 

 Stimulation by means of common salt acts in the same way, but in this case the phenomena of 

 destruction of the centre soon appear. As yet, it has not been proved that there is a similar area 

 for each half of the head. The cerebro-epileptic attacks ( 375) increase the bodily temperature, 

 partly owing to the increased production of heat by the muscles ( 302), partly owing to dimin- 

 ished radiation of heat through the cutaneous vessels, in consequence of stimulation of the 

 thermal cortical nerves. The experiments led to no definite results when performed on rabbits. 

 According to "Wood, destruction of these centres occasions an increased production of heat that 

 can be measured by calorimetric methods, while stimulation causes the opposite result. 



These experiments explain how psychical stimulation of the cerebrum may have an effect 

 upon the diameter of the blood-vessels and on the temperature, as evidenced by sudden paleness 

 and congestion ( 378, III.). 



[Heat Production. Injury to the fore-brain has no effect on the temperature. If the brain 

 of a rabbit be punctured through the large fontanel le, and the stylette be forced through the 

 grey matter on the surface, white matter, and the median portion of the corpus striatum right 

 to the base of the brain, there is a rapid rise of the temperature which may last several days. 

 Injury to the grey cortex does not affect the temperature. After puncture of the corpus stri- 

 atum, the highest temperature is reached only after twenty-four to seventy hours, but when 

 the puncture reaches the base of the brain this result occurs in two to four hours. Electrical 

 stimulation of these areas causes the same effect on the temperature. Direct injury to certain 

 parts of the brain is followed by a rise of the temperature or fever. See also, p. 329, for further 

 evidence of the existence of thermal centres. There is at the same time an increase of the 

 taken in, the C0 2 given off and a decided increase of the N given off, indicating an increase in 

 the proteid metabolism, which points to an increased production of heat (Aronsohn and Sachs, 

 Richet, Wood).'] 



General and Theoretical. Goltz's View. Goltz uses a different method to remove the cortex 

 cerebri he makes an opening in the skull of a dog, and by means of a stream of water washes 

 away the desired amount of brain-matter. He describes, first of all, inhibitory phenomena, 

 which are temporary and due to a temporary suppression of the activity of the nervous 



2 Y 



