XI. THE SUMMARY OF PART IV 321 



molecules might have structural influences upon each other and mole- 

 cules with stronger structure would more or less assimilize others. In 

 this way the evolution of the protein structure itself would have had 

 to continue to proceed for a dreadful span of time before the globulin- 

 like protein which could polymerize orderly to exert strong structural 

 effect could be produced. 



Lipids are not necessary for the production of the strong structure, 

 but if lipids are not inserted among protein molecules, these latter 

 would not be able to change the structure freely so as to be assimilized 

 by the stronger assimilase. The evolution of proteins as well as or- 

 ganisms would never be established without labile structures yielding 

 to assimilation. In addition, free changes of the structure must be the 

 essential feature of life, and thus where there is no lipid there is no 

 life. 



In order to strengthen its pattern and to become stable, the as- 

 similase needs nucleic acids which may raise rigid structure in the 

 polymerization product of proteins. On the other hand, the protein 

 molecules in the assimilase are required to move or change freely for 

 the achievement of various life phenomena, for which the rigidness of 

 the structure is obviously unfavourable. 



The organisms seem to escape fairly from this dilemma by mixing 

 lipids in the greater part of the protoplasm, thereby the protein molecules 

 being rendered easily movable, whereas in its smaller part nucleic 

 acids are inserted instead of lipids to make the structure rigid. Since 

 this smaller part of the protoplasm owing to its rigidness in the struc- 

 ture can remain unchanged even when the greater part containing 

 lipids is altered in its structure, it enables the changed structure to 

 return to its former state, as it can exhibit extensive structural effect 

 by acting as a strong assimilase because of its rigid structure. 



Such part of protoplasm rich in nucleic acid is in higher organisms 

 usually located in nucleus and acts as the standard template of the 

 cell, and is composed of minute particles termed genes. Thus the 

 genes arc a kind of elmentary bodies capable of preventing the deforma- 

 tion of the protoplasm pattern. As the pattern of the gene is, in 

 general, unchangeable, the properties of the organisms can be retained 

 unchanged. 



Various genes are present in the cell of higher organisms and each 

 gene seems to direct each specific, restricted structure of the protoplasm 

 protein. In other words, a gene is composed of protein molecules, only 



