THE NERVOUS SYSTEM 



animals in which the operation has been carried out, as for example in the 

 rabbit and rat, a result very similar to those observed in the case of the frog 

 and pigeon has been obtained. The animal is able to maintain its equi- 

 librium, to run or jump, and in fact successfully carry out the most compli- 

 cated co-ordinated movements, but it is unable to originate them without stimu- 

 lation. 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 re- 

 sponded 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 stimulating 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 co-ordinated move- 

 ments in these animals is 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 CEREBRAL 



CORTEX. 



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

 stimulation have demonstrated that there are definite regions of the cerebral 



