1915] 



MERRILL DISTILLED WATER 461 



stances, notably copper, in solution produced injurious ef- 

 fects on organisms (Spirogyra), and to this phenomenon he 

 applied the term < ' oligodynamik ' ' action. This line of work 

 was extended to include other substances and other organisms, 

 and claimed the attention at different times of Aschoff ('90), 

 Loew ('91), Locke ('95), Ringer ('97), Copeland and Kahlen- 

 berg ('99), Deherain and Demoussy ('01), Lyon ('04), 

 Bokorny ('05), Hoyt ('13), and others. It is of particular 

 interest to note that Ringer in some of his earlier work 

 ascribed the injury to the extraction from the organism of 

 necessary nutrient materials; but after the publication of 

 Locke's experiments ('95), which Ringer duplicated and con- 

 firmed, the latter concluded that the injury done in the par- 

 ticular case under consideration (Tubifex) was due to dele- 

 terious materials in the distilled water. He says : ' ' Copper 

 in even infinitesimal quantities will disintegrate tubifex 

 whilst water free from copper or other heavy metals and 

 without any salts such as calcium salts can sustain the life 

 of tubifex. ' ' 



In regard to the third idea pertaining to the effects of dis- 

 tilled water on organisms, early workers, both on the plant 

 and animal side, found that salts were extracted from 

 organisms placed in distilled water, even though their methods 

 for determining the extraction were somewhat crude. Among 

 the early investigators on the animal side may be mentioned 

 Plateau ('83), Ringer and his school ('83, '84, '85, '94, >94 a , 

 '94 b , '97), Loeb ('03), and others. The writer has another 

 paper ready for publication in which is given a historical treat- 

 ment of the subject of excretions from roots and other plant 

 parts, so the discussion of certain phases of the plant work is 

 reserved for that publication. 



Upon the perfection and the employment of conductivity 

 apparatus by physical chemists, it soon began to be used also 

 by the various workers in the fields of soil, plant, and animal 

 investigations. In this connection distilled water came in for 

 its share of consideration. The determination of the purity 

 of water by ascertaining its electrical conductivity speedily 

 came into vogue, and it should be said that as far as elec- 



