CHAPTER XVI 



CEREBRAL HEMISPHERES AND ASSOCIATIVE 



MEMORY 



i. The view that consciousness is only a meta- 

 physical term for the phenomena determined by the 

 mechanisms of associative memory finds support in 

 the results of experiments on higher animals. Extir- 

 pation of the cerebral hemispheres causes complete 

 loss of associative memory. After this operation, no- 

 thing remains that could possibly be interpreted by 

 the metaphysicians as a phenomenon of consciousness. 



If the cerebral hemispheres of a Rana esculenta or 

 temporaria be extirpated, the frog seems on the whole 

 to be unchanged. This has been proved beyond 

 question by Schrader (i). Such a frog catches flies, 

 buries itself in the mud when the cold season comes, 

 and changes its habitation from the land to the water, 

 like a normal frog. None of these processes, how- 

 ever, are functions of associative memory ; they de- 

 pend upon inherited structures. The frog either has 

 no associative memory or it is so insignificant that it 

 does not in any way affect the behaviour of the frog. 

 This explains the fact that the loss of the cerebral 



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