394 THE EVOLUTION OF MEMORY 



remoteness of aim. Compare, for example, the simplicity of the 

 internal sensationless reflexes of a butterfly, and the immediate 

 ends to which they are directed, with the complexity and remote- 

 ness of aim of the actions to which he is aroused by feelings of 

 hunger or sexual desire, or by the sight of danger. Lastly when, 

 owing to the evolution of many reflexes and instincts, the nervous 

 system had grown highly complex, memory arose, though not of 

 course as a necessary consequence of the complexity. This also 

 was new and unlike anything that had formerly existed in nature. 

 Memory, the name we apply to the power of making mental 

 acquirements, of growing mentally in response to the stimulus of 

 experience, is strictly the counterpart, the homologue, of the power 

 of growing physically in response to the stimulus of use. Indeed 

 the physical power may be termed the physical memory, while the 

 additions made to our bodies through it are the homologues of 

 the mental growth, the stored experience, which results from the 

 exercise of the mental power. In both cases, as we have seen, 

 the powers are ' innate ' or nutritional characters found only in the 

 higher animals, and in their greatest developments only in the 

 highest. Probably they originated about the same time, and 

 perhaps in the same type of living beings. 



652. Memory is the power of making mental acquirements. 

 Though we speak of our recollections of past events as memories, 

 yet, strictly speaking, these acquirements are only the contents of 

 memory. The memory itself is purely innate, and is not increased 

 by experience, though the volume of its contents is so increased. 

 In other words, the power of learning does not increase from birth 

 forwards. On the contrary, it diminishes. A young infant, for 

 example, is more capable of learning than an older person. At 

 birth, the mind of a child, except for sensations and a few instincts, 

 is blank. Sights and sounds and other feelings convey no mean- 

 ings to it. But soon, so great is its power of learning, the messages 

 sent by the organs of sense are understood. In a few weeks it 

 evolves order out of chaos, and comprehends to a wonderful degree 

 the world around it. It learns to co-ordinate its muscles, and in a 

 year or two is able to walk and speak a language, and do a vast 

 deal besides. In these early years, the years of man's greatest 

 mental activity, he makes his most valuable and fundamentally 

 indispensable physical and mental acquirements. But, as he 

 becomes more and more completely equipped for the battle of life, 

 his powers of adding to the store slowly decline. In adult life the 

 gains tend to be balanced by the losses. In old age the mental, 



