MOTOR FUNCTION OF THE CEREBRAL CORTEX 577 



to run or jump, and in fact successfully carry out the most complicated coor- 

 dinated movements, but it is unable to originate them without stimulation. In 

 the case of the dog, it has been found impossible to remove the whole brain 

 at one operation. However, Goltz has succeeded in removing both the 

 cerebral hemispheres of the dog by doing the operation in successive stages 

 and taking extraordinary precautions to protect his animal against the great 

 fall of temperature and the immediate shock of the operation. He kept his 

 dog alive for some eighteen months and secured a complete recovery from the 

 series of operations. Goltz 's dog was able to walk about, it responded to a 

 bright light by closing its eyes, and could be aroused by a sharp, loud sound. 

 It spent its time lying down in the cage, sleeping rolled up dog-fashion. 

 When aroused by stimulation of the skin, it would move away from the stim- 

 ulating object and would sometimes growl and snap at the object. If it snapped 

 at the object it would do so without going toward it or making the usual effort 

 to seize the object which we are accustomed to expect of a normal vicious 

 dog. This dog did not spontaneously feed itself, but had to have food placed 

 in its mouth before it would swallow. But the animal finally learned to take 

 food, as in the case of the pigeon. This animal gave very definite responses 

 to its condition of nourishment; it slept quietly and was peaceful when fully 

 fed, but was restless and irritable when hungry. 



Goltz's dog showed complete absence of those activities which we would 

 call psychic. That is to say, it showed no memory signs, it was unable 

 to learn the signal for feeding, it did not manifest any fondness or signs of 

 pleasure at the presence of its caretaker. In short, there was a complete 

 loss of memory and intelligence, and the animal, although performing some 

 activities, was in fact reduced to a mere automaton. It would be difficult to 

 imagine a more crucial experiment to elucidate the function of the cerebral 

 cortex. 



It is quite evident that the apparatus for carrying out coordinated move- 

 ments is in these animals not localized either in the cerebrum or in the spinal 

 cord. It must therefore be connected in some way with the parts of the 

 brain below the cerebrum and above the cord. There is no reason why such 

 an arrangement may not be supposed to exist in the human brain, although 

 we must look upon the cerebrum as the originator of voluntary movements. 



LOCALIZATION OF THE MOTOR FUNCTION OF THE CERE- 

 BRAL CORTEX. 



The experiments upon the brains of various animals by means of electrical 

 stimulation have demonstrated that there are definite regions of the cerebral 

 cortex the stimulation of which produces definite movements of coordinated 

 groups of muscles of the opposite side of the body. Fritsch and Hitzig were 

 the first to show that the cerebral cortex responds to electric irritation. They 

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