■i 
-  5S0  Relations  of  Plants  to  Distilled  Water,  j A™-  3o™- 
J  l   December,  1915. 
important  one,  and  it  will  require  much  experimentation  for  the 
ultimate  solution  of  all  phases  of  the  problem  involved.  While  the 
results  herewith  reported  are  only  preliminary  in  their  nature,  the 
fact  that  they  give  positive  indications  along  certain  lines  has  been 
deemed  sufficient  warrant  for  their  publication  at  this  time.  In  addi- 
tion to  determining  the  growth  relations  of  plants  in  this  and  other 
media,  consideration  has  also  been  given  to  the  effect  produced  by 
growing  plants  in  this  medium  as  determined  by  means  of  electrical 
conductivity  measurements. 
II.  Historical  Aspects  of  the  Subject. 
The  relation  of  plants  to  distilled  water  is  a  matter  that  has  been 
under  more  or  less  serious  consideration  at  different  periods  for  a 
long  time.  Woodward  (1699),  who  first  employed  the  method  of 
water  culture  in  1691-1692  in  his  interesting  experiments,  found  that 
plants  grew  better  in  river  water  than  in  either  rain  water,  spring 
water,  or  distilled  water.  The  difference  was  of  course  due  to  the 
quantity  of  plant  food  contained  in  the  medium,  and  this  idea,  coupled 
also  with  the  character  of  the  nutrients,  has  been  the  basis  for  a  vast 
amount  of  physiological  work  since  that  time. 
Coming  down  to  more  modern  times,  there  has  been  a  diversity 
of  opinion  among  the  investigators  of  the  subject  in  regard  to  the 
reason  why  plants  and  animals  thrive  so  much  better  in  natural  water 
or  aqueous  media  than  in  distilled  water.  Considering  the  period  from 
about  i860  on  down  to  the  present,  the  most  important  explanations 
offered  may  be  summed  up  under  the  following  three  heads : 
1.  Lack  of  essential  nutrients; 
2.  The  presence  of  deleterious  substances ; 
3.  Extraction  of  salts,  or  nutrient  materials,  from  the  organism 
immersed  in  the  distilled  water. 
Holding  each  of  these  views  there  has  been  a  formidable  array  of 
scientists  at  different  periods,  each  group  contending  strongly  to  estab- 
lish the  correctness  of  its  viewpoint. 
Among  the  earlier  workers  in  the  field  may  be  mentioned  Boehm 
('75),  Deherain  ('78),  and  others,  who  believed  that  the  lack  of 
essential  nutrients  in  the  distilled  water  was  responsible  for  the  re- 
sulting poor  condition  of  the  organism.  Boehm,  for  example,  be- 
lieved that  calcium  played  a  fundamental  role  in  the  metabolism  of 
the  plant,  and  that  in  its  absence  certain  processes,  notably  that  of 
