AmM*arch;i906.rm'}      Purification  of  Drinking  Water.  141 
ease,  it  is  obvious  that  the  disinfection  with  copper  sulphate  should 
begin  here,  and  physicians  should  give  instructions  accordingly.  If 
universal  attention  were  given  to  this  matter,  there  can  be  little 
doubt  that  the  spread  of  typhoid  fever  would  be  prevented  almost 
entirely.  But  as  the  matter  cannot  be  absolutely  controlled,  the 
next  best  thing  is  to  disinfect  the  seivage. 
That  certain  organisms  manifest  a  specific  sensitiveness  towards 
copper  was  first  pointed  out  by  Naegeli.  Following  the  lead  of 
Naegeli,  Israel  and  Klingmann  (1897)  showed  that  copper  foil  has 
a  marked  toxic  effect  on  certain  bacteria,  as  Bacillus  coli  and  the 
organisms  producing  typhoid  fever  and  cholera.  To  Moore  and 
Kellerman  (1904)  belongs  the  credit  of  first  showing  the  application 
of  the  results  obtained  by  Naegeli  (on  algae)  and  Israel  and  Kling- 
mann (on  bacteria)  in  the  purification  of  water  supplies. 
As  the  methods  used  in  my  work  have  been  published  and  are 
readily  accessible,  it  will  probably  be  sufficient  to  call  attention  to 
some  of  the  main  features  of  the  work. 
(1)  The  copper  used  was  in  the  form  of  sheet  copper  or  copper 
foil,  pieces  approximating  9  centimeters  square  being  used  to  each 
1,000  c.c.  of  water. 
(2)  The  organisms  upon  which  we  experimented  were  Bacillus  colt 
and  Bacillus  typhi,  twenty-four-hour  bouillon  cultures  being  used. 
(3)  The  water  used  in  the  experiments  included  filtered,  distilled 
and  tap  water,  all  of  which  were  sterilized  in  an  autoclave  prior  to 
adding  the  cultures  and  copper  foil. 
We  found  in  nearly  every  experiment  which  we  conducted  that 
in  the  water  containing  the  typhoid  or  colon  organisms,  and  to 
which  the  copper  foil  was  added,  these  organisms  were  destroyed  in 
from  two  to  four  hours. 
We  also  found  in  the  parallel  experiments  which  we  conducted 
that  in  the  water  to  which  copper  foil  was  not  added,  the  typhoid 
and  colon  bacilli  continued  to  grow  and  even  multiply  for  months, 
except  in  the  case  of  water  filtered  by  means  of  a  filter  attached  to 
an  ordinary  copper  faucet.  In  the  latter  instance  the  typhoid  or- 
ganisms were  destroyed  in  two  to  four  hours,  just  as  though  copper 
ha  1  been  added  to  the  water,  whereas  the  colon  bacilli  continued  to 
grow,  but  not  as  rapidly  as  in  distilled  or  tap  water.  This  peculiar 
inhibiting  action  of  the  filtered  water  we  subsequently  proved  was 
due  to  a  property  acquired  by  the  water  in  its  slow  passage  through 
