MYSTERIES OF LIFE AND MIND 



while others have two, some three, some four, and 

 even five. So, for example, when wood or coal 

 "burns," the four-armed atom of carbon can seize 

 and hold two of the two-handed oxygen atoms, 

 while in the molecule of water, each of the two- 

 handed oxygen atoms will bind two of the single- 

 handed hydrogen atoms, and so on. 



Chemists, with the old alchemists' love of high- 

 sounding names, called this valency, or atomicity. 



Very early Faraday saw that each "valence," 

 each arm, was able to carry a certain quantity of 

 electricity. Its capacity is fixed. These electri- 

 cally charged atoms, then, are not all alike. The 

 two -armed atoms carry two charges, the three- 

 armed three charges. If, as now seems dimly to 

 be true, what we used to call the loves and hates 

 of the chemical "affinities" was but a name for 

 the action of these electrical charges, then chemis- 

 try, like light, will have been annexed to the wide 

 domain of electricity. 



Professor Loeb's latest work has done much to 

 fix this impression. He has found, for example, 

 that a pure solution of common salt will not keep 

 the heart, or the muscle of the jelly-fish, going. A 

 little calcium added sets things right, though too 

 much will act like a poison. Some of the ions then 

 are toxic, some are antitoxins. Will this turn out 

 to be true of all poisons, that their action results 



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