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Light Reactions at Low Temperatures [Jan. 21, 1910 

 Action of Metals on B. phosphobbsckns. 



Other bacteria have been exposed to the action of ultra-violet 

 light. Bacillus prodigiosus, B. coli communis, B. suMilis, as well as 

 B. phosphorescens are all killed by the action of this radiation at 

 the temperature of - 185° C. 



It is remarkable that any radiation effect should take place in 

 these organisms at liquid air temperature, when of course they are 

 hard solids, and no question of ordinary chemical interaction between 

 liquids or gases is possible, as in the case of such powerfully reacting 

 agents as fluorine and liquid hydrogen, which explode violently when 

 brought together under such conditions. Ozone from solid oxygen 

 is, of course, another example of a chemical change taking place at 

 the boiling point of hydrogen, which in this case is induced by the 

 ultra-violet radiation. Any action that takes place must be in the 

 solid contents of the bacteria, which seem to be actually broken up, 

 when examined microscopically after exposure to the ultra-violet 

 light. Perhaps the production of electrically charged ions through 

 the action of the short wave length radiation on the surface of the 

 solid organisms, is a potent factor in theit destruction at low tem- 

 peratures. In any case, it seems the protoplasmic molecule cannot 

 stand the internal strain produced by the vibrations set up in it by 

 the action of the rays of short wave-length, and is thereby forced to 

 re-arrange its atomic structure, causing the death of the organism. 



These are only a few indications that there is still much low 

 temperature chemistry to be worked out. 



[J. D.] 



