A™Ma?Sb,fM6.rnj'}      Purification  of  Drinking  Water.  143 
The  effects  of  oligodynamic  copper  in  the  purification  of  drinking 
water  are  in  a  quantitative  sense  much  like  those  of  filtration,  only 
the  organisms  removed,  like  Bacillus  typhi  and  Bacillus  coliy  are 
completely  destroyed. 
THE  EFFECTS  OF  WATER  TREATED  WITH   COPPER  ON  MAN. 
While  it  has  been  conclusively  shown  that  exceedingly  minute 
quantities  of  copper  are  toxic  to  typhoid  organisms,  still  the  ques- 
tion is  raised  by  some  as  to  the  toxic  effects  on  man  when  copper  or 
its  salts  are  used  in  the  purification  of  drinking  water.  In  comment- 
ing on  a  paper  of  mine  on  "The  Efficiency  of  Copper  Foil  in 
Destroying  Typhoid  and  Colon  Bacilli  in  Water,"  a  reviewer  writes 
as  follows :  "  While  recommending  the  use  of  copper  foil  for  the 
purification  of  drinking  water,  the  writer  adduces  no  proofs  as  to 
freedom  from  toxic  effects  when  water  so  purified  is  taken  into  the 
system  over  a  considerable  period  of  time."  My  reason  for  not  tak- 
ing up  the  pharmacological  phase  of  this  question  heretofore  has 
been  that  my  own  experiments  in  the  consumption  of  water  treated 
with  copper  foil  did  not  extend  over  a  sufficient  period  of  time  to 
warrant  me  in  making  any  statements  in  regard  to  the  effects  of 
water  so  treated.  Then,  too,  I  felt  that  the  statements  of  pharma- 
cologists and  physiologists  were  conclusive  as  to  the  probable 
harmlessness  to  man  of  copper  when  used  in  the  proportions  neces- 
sary to  purify  water  containing  typhoid  organisms.  But  since  there 
seems  to  be  some  objection  in  certain  communities  to  the  drinking 
of  water  treated  with  copper,  I  have  deemed  it  advisable  to  give  my 
own  experience  in  connection  with  this  subject. 
For  nearly  a  year  all  of  the  drinking  water  consumed  in  my  home 
has  been  treated  with  copper.  A  strip  of  copper  foil,  or  sheet  cop- 
per, 9  inches  square,  is  placed  in  a  vessel  containing  from  3  to  4 
quarts  of  water  and  allowed  to  remain  from  four  to  eight  hours. 
The  foil  is  first  cleaned  with  powdered  pumice,  and  retains  its  lustre 
for  weeks  unless  the  water  contains  a  considerable  quantity  of  sedi- 
ment, and  provided  the  quantity  of  water  is  renewed  immediately 
each  time  upon  drawing  off  the  sterilized  or  purified  water.  On  ac- 
count of  the  varying  amounts  of  sediment,  we  find  it  desirable  to 
filter  the  water  before  treating  it  with  copper  foil.  Up  to  this  time 
no  ill  effects  have  been  noted  from  drinking  the  water  so  treated, 
and,  in  fact,  our  general  health  may  perhaps  be  said  to  be  better 
