THE SUMMARY OF PART V 441 



completely, the more frequently occurs the repetition of the change. 

 The memory is, therefore, a structural pattern of proteins, given rise 

 to by the removal of the structural factors which prevent the rever- 

 sible change. 



Proteins produced as replicas of memory-carrying proteins, which 

 constitute the protoplasm acting as a template, must consequently have 

 the memory. The memory in our brain may thus be established. As 

 the structural pattern specific to a memory is transferred to newly 

 synthesized proteins, the memory can continue for life. 



On the other hand, the structural pattern involving a memory also 

 has the tendency to recover its original pattern to produce again the 

 preventing structural factors, and therefore the persistence to the 

 original pattern render the reversible change difficult leading to the 

 oblivion of the memory. Hence, for the maintenance of memory is 

 needed the repetition of the reversible change, namely continuous 

 training, thereby the production of preventing structural factors is 

 inhibited. 



In addition, if a protein remains under the same environmental 

 condition in taking the structure determined by the environment, the 

 structure will be gradually altered so as to be more fitted to the 

 environment, so that the structure is fixed and its change in any 

 directions becomes difficult, thus the original structure being forgotten. 



The gradual alteration of protein structure to be fitted to the 

 environment is the adaptation of the protein to the environment, and if 

 the adaptation goes so far as the structure becomes too fixed to lose 

 its elasticity it may be called senescence. 



Individual development may be based upon the reversible character 

 of proteins constituting the genes of germ cells. It is considered that 

 a germ cell can act as an independent, unicellular organism because 

 of the primitive structure of its protoplasm and that this primitiveness 

 is brought about by the structural return of a certain somatic cell to 

 its primitive stage, from which the organism producing the germ cell 

 has been developed. Such a return to the primitive structure must be 

 brought about by the reversible character of protoplams protein. Since 

 the structure of the protoplasm is governed by the genes, the return 

 of the protoplasm to the primitive structure must be raised by the 

 structural change of the genes. The structure of the genes may be 

 reduced to the primitiveness under the influence of a factor or factors 

 that make the primitive structure more stable than the developed. 



