764 General and Applied Biology 



away from light, while leaf stalks bend so that the leaves secure the 

 necessary amount of light. This bending is due to the unequal amount 

 of growth on opposite sides of the stem or root. Light, gravity, and 

 contacts may influence this unequal growth. Possibly, all living proto- 

 plasm is affected by light to a greater or lesser extent, depending upon 

 its degree of complexity. 



Bioelectric Phenomena 



Many recent experiments have tended to prove that a number of 

 biologic phenomena are associated with electricity. When an acid col- 

 loid is separated from an alkaline colloid by a semipermeable, dielectric 

 membrane or film, there is formed an electric cell within which an elec- 

 tric potential exists between the acid-positive nucleus and the alkaline- 

 negative cytoplasm. The thin lipoid films surrounding the nucleus and 

 cytoplasm ofTer definite resistance to positive hydrogen ions, while in 

 death this resistance is lowered. The maintenance of the acid-alkali 

 balance between the nucleus and cytoplasm of cells (the electric poten- 

 tial) is essential to life and furnishes the energy of the living processes. 

 The reduction of it to equilibrium (zero) results in death. The vital 

 potential in cells is due to oxidation, and this oxidation in turn is gov- 

 erned by the electric potential acting as a physical catalyst within the 

 cell. Hence, we have the source and a controlling factor of the elec- 

 trical phenomena associated with cells. Because of its high rate of 

 oxidation, the comparatively acid nucleus supplies vital force in the 

 form of electrical energy. Because of its higher electric potential (ten- 

 sion), the nucleus sends interrupted currents toward the cytoplasm, the 

 currents following each other in rapid succession. As the electric poten- 

 tial of the nucleus increases, the current breaks through the nuclear 

 membrane; the potential of the nucleus then falls and the current stops 

 momentarily; oxidation immediately restores the potential in the nucleus 

 with another discharge into the cytoplasm, which explains the inter- 

 rupted currents passing from the positive nucleus to the negative cyto- 

 plasm as well as the accumulated charges on the surface of the mem- 

 branes. The nuclear membrane and the plasma membrane are both 

 lipoid films, semipermeable, exquisitely thin, and with high dielectric 

 (nonconductive) capacities. The thinner this lipoid film, the higher the 

 electric charge or capacity. 



Water is an important catalyst and has an extremely high dielectric 

 constant. Water holds an infinite variety of substances in solution and 



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