MYSTERIES OF LIFE AND MIND 



other negatively. In the case of ordinary salt, so- 

 dium chloride, the metal atoms of sodium take 

 the positive charge, the chlorine atoms the nega- 

 tive. These electrically charged atoms, long be- 

 fore their nature was understood, Faraday named 

 ions. 



This simple conception has revolutionized mod- 

 ern chemistry. In the famous phrase of Arr- 

 henius, "it is the ions which act." And it is the 

 ions which may cause the heart or a muscle to 

 contract. The negative charges set them going. 

 The positive charges stop them. Such, in an ex- 

 tremely popular presentation, is the essence of this 

 remarkable work. In the new view, the ultimate 

 cause of muscular action, and, not improbably, of 

 all life-processes, is electricity. 



The applications of this conception are wide. 



If the apparently simple question of solutions 

 was the hardest problem of the chemists, that of 

 the beginnings of life, the process of fertilization, 

 was the burning question of biology. From the 

 countless myriads of eggs produced by the female 

 organism, and the equal hordes of the sperm-cells, 

 a single egg, a single sperm, unite to form the 

 single microscopic cell from which all forms of 

 animal life originate. Unfertilized by the male 

 cells, the eggs quickly degenerate and die. 



All the problems of life, growth, heredity too, lie 

 K 209 



