Herrick, Cortical Motor Centres. 97 



and 2 to the fore leg and i is on the border between the two 

 regions. 



A large series of stimulation experiments on the musk rat 

 (Fiber) are passed over as wholly ambiguous or contradictory. 

 Fig. 4, b illustrates a case of extirpation in this subject. Previ- 

 ous electrical stimulation of the cephalic part of this area re- 

 sulted in motions of the fore foot for the most part. After re- 

 covery from the operation there was very evident impairment of 

 the power of abduction in the manus and pes of the right side. 

 When pushed towards the right the animal offers no resistance 

 and may be turned upon its back, while the effort to push it to- 

 ward the left is met by decided resistance. Tactile sensation is 

 also weakened on the right side, as shown by the reaction to 

 the needle. A second specimen was deprived of the cortex 

 within the foreleg region and, after recovery, some impairment 

 of the motion of the opposite fore-leg was apparent. The ani- 

 mal seemed unable to extend the fingers and the fingers double 

 under while walking. It is easy to push the animal over to- 

 ward the injured side. On the other hand the coordinated mo- 

 tions like those of washing the face are carried out without dif- 

 ficulty. In another specimen a larger area was removed extend- 

 ing further caudad. Fig. 4, c. 



The symptoms were much the same except that there is a 

 greater apparent involvement of the hind limb. Loss of muscu- 

 lar sense is suggested. The power of adduction seems to have 

 suffered most. After 10 days recovery is nearly complete, at 

 least so far as locomotion is concerned, but there is a curious 

 awkwardness, hard to describe but easily recognized. When 

 sitting up it tends to fall toward the side opposite to the lesion. 

 Vision was permanently destroyed in the eye of the opposite 

 side. After 20 days all efforts to provoke motion result in ro- 

 tation to the right. This is due, in all probability, to the ex- 

 tension of the effect of the injury by inflammatory processes. 

 In yet another case in which the same area was removed the 

 rotation began soon after the operation and continued till it ter- 

 minated in convulsions. The animal was blind in the opposite 

 eye. 



