Amjinef'i905arm"}     Use  °f  Copper  in  Destroying  Typhoid.  279 
Pasteur1  says  :  "  In  regard  to  the  toxicity  of  copper  salts,  it  may 
be  said  it  is  almost  impossible  to  take  a  dose  large  enough  to  pro- 
duce death,  both  from  their  horrible  taste  and  from  the  violent 
vomiting  which  they  produce.  In  small  quantities  the  taste  is  not 
perceptible,  and  the  salts  are  not  only  tolerated  but  absorbed. 
Workers  in  copper  are  often  completely  saturated  with  the  metal, 
but  do  not  suffer  from  it.  Experiments  on  animal  and  human  sub- 
jects have  never  given  a  worse  result  than  vomiting  or  a  temporary 
fit  of  colic.  Copper  normally  exists  in  the  human  body.  It  gains 
entrance  from  various  foods  and  drinks  in  the  absence  of  all  adultera- 
tion. It  accumulates  to  a  certain  extent,  but  injury  from  this 
accumulation  is  unknown.  In  the  samples  submitted,  copper  exists 
to  an  extent  varying  between  16  and  45  milligrammes  per  kilo- 
gramme. .  .  .  The  quantity  found  does  not  constitute  a  danger 
to  health." 
CONCLUSIONS. 
(1)  It  is  pretty  well  established  that  the  typhoid  organism  is  dis- 
seminated not  only  through  water,  but  also  through  air  and  food, 
and  may  retain  its  vitality  for  a  considerable  period  of  time. 
(2)  Typhoid  organisms  in  water  are  eliminated  by  filtration,  boil- 
ing and  certain  biochemical  methods.  Of  the  latter,  the  use  of 
copper,  as  proposed  by  Moore  and  Kellerman,  is  probably  the  most 
efficient  and  at  the  same  time  most  practicable. 
(3)  While  exceedingly  minute  quantities  of  copper  in  solution  are 
toxic  to  certain  unicellular  organisms,  as  bacteria,  it  is  safe  to  assume 
that  the  higher  plants  and  animals,  including  man,  are  unaffected 
by  solutions  containing  the  same  or  even  larger  amounts  of  copper. 
(4)  There  being  a  number  of  factors  which  tend  to  eliminate 
copper  from  its  solutions,  it  is  hardly  likely  that  there  would  be  any 
copper  in  solution  by  the  time  the  water  from  a  reservoir  reached 
the  consumer  if  the  treatment  of  the  reservoir  were  in  competent 
hands. 
(5)  Many  plants  contain  relatively  large  quantities  of  copper,  and 
when  these  are  used  as  food  some  of  the  copper  is  taken  up  by  the 
animal  organism,  but  there  are  no  records  of  any  ill  effects  from 
copper  so  consumed. 
1  Ann.  d'Hyg.y  publ.  Par.,  3d  ser.,  v.  3,  p.  204.    Mars.,  1880. 
