THE ('Kit KB HUM 129 



and individuality becomes inevitable. Memory is used 

 in two senses. Speaking subjectively, we use it to mean 

 conscious recollection. We can use it in a purely objec- 

 tive way to mean no more than the modification of 

 reactions resulting from individual contacts with the 

 environment. When we say that "the burnt child dreads 

 the fire" we usually mean that the child recalls with dis- 

 tress an unfortunate occurrence in its past. But the con- 

 dition can be indicated in quite another way. We may say 

 that the nervous system of the child has been so altered 

 by a past impression upon it that it will cause the child 

 to draw back from the fire. A type of action is implied 

 which is essentially reflex. 



The boy, like the moth, may be attracted by the flame 

 until the negative reaction has been established; the 

 difference between the two nervous systems compared 

 lies to a great extent in the capacity of the higher one to 

 be modified by use, the lower one persisting in its heredi- 

 tary response regardless of consequences. The burnt 

 moth probably does not "dread the fire" in either the 

 psychologic or the physiologic sense. The contrast set 

 forth is that between a system without any part closely 

 corresponding to a cerebrum and one in which this de- 

 partment is dominant. 



The general conception outlined is justified by the 

 results of experiments in which animals of various kinds 

 are deprived of their cerebral hemispheres and kept alive 

 for observation. The consequences of the loss are grave 

 just in proportion to the part played by individual ex- 

 perience in the government of the organism. Most fishes 

 survive the operation with no clear sign of deficiency. 

 When this is not strictly true it is because the particular 

 fish studied has been one which was regulated in its move- 

 ments by the impulses derived from the organ of smell. 

 It must not be forgotten that this sense organ and no 

 other is detached from the remainder of the nervous 

 system when the cerebrum is destroyed. It is said that 

 sharks, which have been made "decerebrate," as the term 



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