ANATOMICAL AND PSYCHIC LOCALISATION 269 



not caused any clinical symptoms. It is obvious that 

 certain organs are more easily disturbed by a lesion 

 in the cortex than others. An operation in the centre 

 of the fore-leg produces disturbances more easily than 

 an operation in the centre of the hind-leg. There 

 are certain parts of the body in which no disturbances 

 can be produced by the extirpation of their so-called 

 centres in the cortex. Nobody has thus far been able 

 to produce a paresis or paralysis of the upper eyelid 

 in a dog or to produce loss of sensibility in the cornea 

 by an operation in the cortex. It must, moreover, 

 not be overlooked that all the disturbances which 

 follow small lesions of the cortex in dogs are only 

 transitory. 



5. Not only the motor but also the sensory disturb- 

 ances which follow an operation in the cerebral 

 hemispheres have been interpreted as psychic dis- 

 turbances. We know that a lesion of the surface of 

 the occipital lobes causes visual disturbances. Munk 

 has interpreted these disturbances which follow a 

 small lesion of one of the visual spheres as psychic 

 (4). There is a small region (Aj Fig. 39) in each of 

 the occipital lobes the destruction of which, according 

 to Munk, causes a psychic blindness in the opposite; 

 eye. By psychic blindness Munk means the fact that 

 the dog does not recognise what it sees, although it is 

 by no means blind. If the cortex be removed at the 

 region A 1 in the left hemisphere, the dog shows psychic 

 blindness in the right eye. Such a dog, for instance, 

 is no longer afraid of a burning match or of the whip, 



