LOCALISATION IN THE CORTEX CEREBRL 



725 



movements of a limb or other part of the body, is followed by entire loss 

 of sensibility in that limb. 1 



Even if this assertion of Munk's were true, it would by no means 

 justify the exclusion of the 

 expression " motor " from the 

 designation of a part of the 

 cerebral cortex which is di- 

 rectly functionally connected 

 with the motor apparatus of 

 the spinal cord and bulb. 2 

 It is, however, not the case 

 that sensibility is lost in 

 the paralysed part, and it 

 is difficult to comprehend 

 that the assertion should 

 have been made and that it 

 should be reiterated. It is 

 certain that in the monkey 

 the careful and complete re- 

 moval of the whole of the 

 region of the cortex, ex- 

 citation of which produces 

 movements in the opposite 

 hind-limb, may not be fol- 

 lowed by any discoverable 

 sensory paralysis of the limb 

 in question; 3 although the 

 limb is absolutely devoid of 

 the power of executing any 

 true voluntary movements, 

 and although the entire re- 



moval of its cortex may be 

 proved by the fact that it 

 does not participate in an 

 epileptic fit, induced by arti- 

 ficial stimulation of other 



FIG. 380. Brain of monkey, marked out into the 

 so-called "sensory areas". A, visual sphere ; B, 

 auditory sphere ; CtoJ, tactile spheres. C of leg ; 

 D of arm ; E of head ; F of eyes ; G of ear ; H of 

 neck ; J of trunk. After H. Munk. 



" After total extirpation of the arm and leg area, tactile sensibility of the opposite 

 extremities is permanently lost ; a touch or light pressure is without any effect, neither 

 tactile reflexes nor eye nor head movements are produced. The same is the case if the 

 whole of the arm or leg region is removed in monkeys ; tactile sensibility is permanently 

 lost in the opposite arm or leg" (H. Munk, " Ueber die Fuhlsphare der Grosshirnrinde, 

 Fiinfte Mittheilung," Sitzungsb. d. k. Akad. d. Wissensch. zu Berlin, November 5, 1896). 

 Further, "Schiff was right in affirming the existence of sensory disturbances, local 

 anaesthesias. The parietal lobe is therefore the tactile sphere, as the temporal is the 

 auditory and the occipital the visual sphere. One can roughly say that, as the retina is 

 projected on the visual so is the skin on the tactile sphere. "The affirmation that 

 lesions of the cortex in the region of the parietal lobe produce purely motor disturbances, 

 without accompanying sensory defects, has been shown to be erroneous" (!). 



2 Although as a matter of fact the fibres of the pyramidal tract do not terminate 

 amongst the cells of the anterior horn of the spinal cord, as has hitherto been supposed, 

 but amongst the cells of Clarke's column and of the base of the posterior horn (Schafer, 

 "Proc. Physiol. Soc.," 18th March 1899, Journ. PhysioL, Cambridge and London, vol. 

 xxiv.), and their connection with the motor cells must therefore be indirect, it is none the 

 less the case that the impulses they convey must be efferent, but whether motor or in- 

 hibitory, or both, is not known. Perhaps the fibres which go to the homonymous lateral 

 column are inhibitory ; while those to the heteronymous side are motor. 



3 Schafer, Journ. "Physiol., Cambridge and London, 1898, vol. xxiii. p. 310. 



