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the structure or functions of animals was noted by Kolliker (5) working 
on the irritability of nerves, by Nasse (6) dealing with the supporting 
power of various solutions for frog's muscle, and a little later by Sydney 
Ringer (7) working on the survival of fishes in different media. 
Harmful Impurities Sought. — The existence of harmful properties 
in distilled water being recognized, many investigators working along 
several lines of biological and chemical study have endeavored to 
ascertain the reason for the results observed. 
As would be expected, the search for poisonous substances in the 
water has been thoroughly prosecuted and many investigators have 
believed the problem solved by results obtained along this line. 
In 1 89 1, Loew (8) called attention to the work done on distilled 
water by Nageli (9) in -an investigation probably begun in the early 
eighties, but unpublished until 1893 after his death. In this paper, 
he showed that distilled water from metal stills was contaminated by 
compounds of the metals coming in contact with the water. These 
results confirmed by Loew (8), Locke (10), Ringer (11), Deherain & 
Demoussy (12), Bokorny (13) and others working in diverse fields of 
biological research, seemed greatly to simplify the distilled water 
question. Water distilled from glass was regarded as a well under- 
stood and safe medium for physiological work. This comfortable 
conclusion, however, was not allowed to stand unchallenged. 
More recently a number of investigators have asserted that water 
distilled from glass even with the usual precautions is harmful, through 
the action of impurities present. Lyon (14) and later Livingston (15) 
and his associates in the Bureau of Soils of the U. S. Department of 
Agriculture convinced themselves that distilled water thus prepared 
contained both volatile and non-volatile unknown poisons. Lyon 
suggested that dissolved ammonia might be the harmful agent. 
Harmful Properties of Pure Water. — Early in the history of the 
problem it was noted by Knop (16), Zobl (17) and others among the 
plant physiologists and by Paul Bert (18), Plateau (19, 20) and Sydney 
Ringer (7) among the animal physiologists that organisms lose salts 
when brought into solutions relatively lacking in these constituents 
and the harmful effects due to this extraction of materials was pointed 
out. Detailed information concerning the materials extracted was 
worked out by Knop (16) and Zobl (17), while Ringer (7) hazarded 
some well considered surmises. This study was prolonged by Ringer 
(21-24) and his associates through a number of succeeding years by 
the use of a variety of methods and of experimental subjects. 
