576  The  Copper  Treatment  of  Water.      { A^cimbelhmt 
their  investments  and  their  labor  extending  over  some  years  might 
not  be  entirely  lost  by  the  introduction  of  this  comparatively  simple 
and  inexpensive  mode  of  water  purification. 
The  question  of  the  danger  from  the  use  of  copper  sulphate  in  the 
manner  set  forth,  has  been  shown  by  Dr.  Moore  to  be  practically 
without  foundation,  it  being  consumed  in  much  larger  quantities  in 
certain  foods  at  a  single  meal  than  would  be  obtained  from  a  much 
larger  quantity  of  water  than  would  be  consumed  in  a  single  day. 
It  may  not  be  amiss  to  refer  to  Cushny's  "  Pharmacology  and 
Therapeutics  "  in  this  connection,  the  work  having  been  published 
in  1899,  and  the  statements  showing  the  peculiar  behavior  of 
copper  being  prophetic  in  a  measure.  He  states  that  while  it  is 
comparatively  harmless  to  man,  yet  it  is  exceedingly  toxic  to  micro- 
organisms.and  intestinal  parasites.    Cushny  says: 
"  Small  quantities  of  copper  may  be  taken  for  indefinite  periods  without  any 
symptoms  being  induced,  so  that  so  far  as  man  is  concerned  the  general  action 
of  copper  is  unknown  On  the  other  hand,  copper  is  a  deadly 
poison  to  several  of  the  lower  plants.  Thus,  traces  of  copper  added  to  the 
water  in  which  they  live,  destroy  some  of  the  simpler  algae,  and  Naegeli  asserts 
that  1  part  of  copper  in  1,000,000,000  parts  of  water  is  sufficient  to  kill  these 
plants  Locke  found  that  the  traces  of  copper  contained  in  water 
distilled  in  copper  vessels  were  sufficient  to  destroy  tubifex  (one  of  the  annelid 
worms)  and  tadpoles,  while  Bucholtz  states  that  the  development  of  bacteria  is 
stopped  by  a  solution  of  copper  sulphate  under  1  per  cent,  in  strength.  Cop- 
per thus  seems  to  have  a  very  powerful  poisonous  action  on  certain  living  forms 
and  to  be  harmless  to  others,  and  the  subject  deserves  further  investigation. 
It  is  possible  that  it  may  prove  to  act  prejudicially  to  some  human  parasites, 
and  it  is  certainly  less  dangerous  to  man  than  many  other  remedies  used  as 
parasiticides  and  disinfectants." 
The  influence  of  the  copper  method  in  retarding  the  establish- 
ment of  nitration  plants  would  scarcely  be  any,  it  being  proposed,  as 
clearly  stated  by  Dr.  Moore,  to  apply  this  method  to  the  purifica- 
tion of  water  containing  pathogenic  organisms,  only  as  an  emergency 
proceeding  or  as  a  supplementary  measure,  as  when  there  are  leaks 
in  the  filter  or  the  filter  is  inefficient  for  any  other  reason,  or  when 
there  is  no  filtration  system.  Notwithstanding  the  copper  sulphate 
treatment,  filtration  would  still  be  necessary  for  the  removal  of  the 
excess  of  suspended  matter  from  water  supplies.  While  it  is  true 
that  there  are  chemical  methods  of  sedimentation,  nothing  practi- 
cable on  a  large  scale  has  as  yet  been  suggested. 
In  testing  the  value  of  copper  sulphate  for  reducing  the  number 
