122 HUMAN PHYSIOLOGY 



Decerebrate frogs would pass for perfect animals if 

 the inspection were not quite patient and conscientious. 

 Those who have studied them most closely tell us that 

 they are rather more machine-like or less ''spontaneous" 

 than intact frogs. They are liable to blunder against 

 obstacles and they will not surely save themselves from 

 death when gradually heated in a pan of water. This is 

 in spite of the fact that they jump with vigor when 

 stimulated in other ways. It is claimed that a frog 

 which has learned anything how to escape from a 

 certain enclosure, perhaps will lose the accomplish- 

 ment when decerebrated. If this is correct it is of the 

 utmost interest for it foreshadows the special property 

 of the cerebrum higher in the scale. 



Those animals which we feel warranted in calling 

 " lower" are admirable mechanisms to work under fixed 

 conditions. What they lack is the power to profit by 

 experience. We cannot say that this is absolutely want- 

 ing in the simplest forms but it is more and more evident 

 as we consider those of higher rank. In precisely the 

 same proportion the cerebrum becomes dominant in 

 the nervous system. The power to profit by experience, 

 to learn, or to acquire new reactions is nearly akin to 

 memory. The statement that the cerebrum is the organ 

 of associative memory can be strongly defended. 



The word memory is likely to suggest to the student 

 conscious recollection. It is quite as correct to use it 

 objectively. In this sense the memory of an impres- 

 sion is a modification of the nervous system manifested 

 through the fact that reactions subsequent to the event 

 are different from what they would be if it had never 

 occurred. A cat when left alone in a room where there 

 is meat on the table is likely to jump up and steal it. 

 After certain punishments the animal may refrain 

 from taking the food. We may say that the cat re- 

 members the blows, or we may exclude all subjective 

 ideas and say that the nervous system has been so 

 changed that it does not react as it did at first. This 



