THE CEREBRUM 315 



Goltz's dog, from which the cerebral hemispheres had been 

 removed, was able to perform all movements, though in 

 a clumsy manner. Its sensations were not impaired. It 

 snarled and growled, but did so to friend and foe ahke. 

 It had no memory, and was only induced to eat when 

 food was pushed up close to its nose. In the dog, then, 

 the functions of the cerebrum are principally psychical. 



The higher in the scale the animal is the more do motor 

 and sensory functions come to be located in the hemispheres. 



FI5SUK£ OF RX)LflNDO Z™^'^''' ""^ESSUI^E ANO 



PASSIVE MOVEMENT 



.vAUDITO- 

 P5YCHIC 



AUDITO-SENSORY VI3U0-5EN50Ry 



Fig. 56. — Principal sensory centres of the brain. 



These functions have already been described, and their 

 location will be readily understood from Figs. 55, p. 310, 

 and 56, p. 315. One further word is necessary. We have 

 seen that the reflex arc, as it travels through the cord, 

 involves at least two and probably three neurones. It 

 enters the cord as a sensory impulse and leaves it as a 

 motor impulse. Where centrally the change from sensory 

 to motor occurs it is impossible to say. Now sensori- 

 motor reactions involving the brain also form a reflex 

 arc, distinguished from a simple spinal arc only by the 

 greater length of its path and the greater complexity of 

 its connections. When, therefore, a motor reaction follows 



