ANATOMICAL AND PSYCHIC LOCALISATION 273 



the irritability of the optical apparatus caused by the 

 operation wears off after a certain time. 



We then come to the conclusion that the apparent 

 psychic blindness which follows the destruction of the 

 region Aj in the opposite hemisphere is exclusively a 

 hemianopia or hemiamblyopia. This disturbance is 

 no psychic disturbance inasmuch as it can be pro- 

 duced by an injury to a peripheral nerve, the optic 

 tract. 



7. We must seek an explanation for the temporary 

 character of the disturbance which follows small 

 lesions. If the lesion covers a large area, the dis- 

 turbance is more permanent. Goltz assumes that 

 these transitory effects are shock-effects due to the 

 operation. He was led to this assumption through 

 his experiments on the spinal cord. If the spinal cord 

 be cut in a dog, no segmental reflexes occur during 

 the first days or weeks after the operation in the part 

 of the animal below the cut. " Pressing on the hind- 

 feet produces no reaction. In the male dog, erection 

 of the penis cannot be aroused reflexly. The urine 

 collects in the relaxed bladder. The anus gaps. In 

 brief, the whole posterior part of the body seems un- 

 irritable. A few days later the apparently dead spi- 

 nal cord may have recovered almost entirely. The 

 posterior part of the animal then offers a large num- 

 ber of reflex phenomena. No one will assume that 

 that piece of the spinal cord which is separated from 

 the brain in so short a time acquires entirely new 

 powers as a reflex organ ; we must assume that these 



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