X. THE CHANGE OF PROTOPLASM STRUCTURE 309 



concentration of K ion in the inside and on the outside of the nerve 

 fibre. The ratio of K ion in the inside to that on the outside is given 

 as 29 : 1. However, during excitation this ratio is changed, the ion 

 present in the inside being liberated. The occurrence of such an ex- 

 change of ions by stimulus can be demonstrated with the help of 

 various isotopes (151). The exchange may be recognized as action 

 current when examined electrically. 



The existence of similar ratio of ions is also known between red- 

 blood cells and the serum : In the cells, K ion is present in a much 

 higher concentration than Na ion, but in the serum the ratio is reverse 

 as in the sea water. K ion seems present in such high concentrations 

 generally in the cell protoplasm, a fact which may depend upon the 

 property of the protoplasm protein to adsorb preferably K ion. This 

 adsorbed K ion, on the excitation, will be eluted by the structural 

 change of the protein, giving rise to an electric disturbance. 



It may, therefore, be concluded that action current is raised by 

 the "absorption and excretion" of inorganic ions. On the other hand, 

 it is known that action current is associated with the true absorption 

 and excretion, a fact which can be expected, since this phenomenon 

 may also be brought about by the structural change of protoplasm as 

 discussed earlier. 



The electric disturbance occurring in the brain may be called brain 

 wave. The function of brain must likewise be given rise to by a 

 similar structural change of the protoplasm protein. The fact that 

 brain current is generally oscillating and wavy, suggests that the 

 structure of the brain protoplasm tends to oscillate regularly. 



The structural pattern of brain may be more or less disturbed 

 and deformed during the constant change of the structure. Its mending 

 may be accomplished by sleep during which no stimulus is given and 

 sufficient time is provided for the recovery of the original pattern ; 

 presumably the reversibility of the protein structure accounts for this 

 recovery. 



Since all the life phenomena must be raised by the structural 

 change of protoplasm, which is always to be accompanied by the 

 electrical disturbance, this latter phenomenon should be "the sign of 

 life" as Waller proposed a long time ago. 



4. The Mechanism of Blood Coagulation. 



The theory of the writer on life phenomena discussed so far is 

 based upon the basic assumption that the structural change of proteins 

 is transmissible. This assumption was made for the first time by 



