THE FORE-BRAIN 



587 



of motor paresis and a certain blunting of cutaneous and muscular 

 sensibility. 



Munk's experiments refer particularly to the effects of isolated 

 extirpation of several regions of his sensory sphere, which are 

 somewhat differently localised in monkeys and in dogs (Fig. 297). 

 His results are a complete contrast to those described for dogs ; 

 the defect phenomena in the different forms of cutaneous and 

 muscular sensibility are perfectly localised to the parts of which 

 the centre had been destroyed. Just as the movements produced 

 by stimulation of different regions of the Rolandic area are due 



FIG. 297. Macacus brain from above and from the side, showing the respective sensory areas 

 as in last figure. (From H. Munk.) 



to, awakening of the sensations which normally accompany such 

 movements, so the motor paralysis consequent on extirpation of 

 these regions is, according to Munk, due to loss of the same sensa- 

 tions. Again, after transection of the dorsal roots of a limb its 

 voluntary motility is largely reduced or abolished (Panizzi, Baldi). 

 It follows logically from Munk's theory that after total extirpation 

 of any one of his sensory areas, for instance area D, there must be 

 total loss of cutaneous and muscular sensibility in the fore-limb on 

 the opposite side. Yet this is not shown either by his own experi- 

 ments, or by those of his numerous opponents. 



Schafer states positively that in the monkey careful and 

 complete removal of the entire region of the cortex, which 011 

 stimulation produces movements of the hind-limb of the opposite 

 side (area 6' of Munk), may not be followed by any obvious 

 sensory paralysis, although the limb loses its power of voluntary 

 movement. The extirpation of the cortex can be shown to be 

 complete by the fact that on exciting an epileptic fit by electrical 

 stimulation of other areas of the cortex, the hind-limb of the 



