268  Use  of  Copper  in  Destroying  Typhoid.    { Am j^19F0Sarm- 
on  truck  farms  renders  it  probable  that  fecal  bacteria,  including 
typhoid,  are  disseminated  through  the  use  of  garden  vegetables.  In 
many  instances  this  manure  is  allowed  to  stand  in  large  pools,  and 
by  means  of  dippers  is  sprinkled  over  the  soil.  In  August,  during 
the  heavy  rains,  I  have  seen  low  plants  like  lettuce  and  spinach 
completely  washed  with  this  more  or  less  dilute  liquid  manure. 
The  experiments  of  Dr.  Lee  show  how  difficult  it  is  to  wash  out 
the  organisms  from  cress,  and  the  same  would  apply  to  vegetables 
like  lettuce  and  celery,  in  the  latter  case  the  soil  being  sometimes 
heaped  up  around  the  plants  to  prepare  them  for  the  market. 
No  doubt  in  many  instances  certain  fruits,  which  are  eaten  in  a  raw 
condition,  as  tomatoes,  apples,  pears,  etc.,  are  sources  of  infection. 
In  a  recent  paper  Dr.  Barringer 1  gives  a  number  of  observa- 
tions which  tend  to  show  that  the  dust  from  American  rail- 
road beds,  through  the  discharge  of  typhoid  patients  while  travel- 
ing over  the  roads  when  in  the  infective  stage,  is  a  probable  source 
of  typhoid  infection,  which  has  not  been  generally  appreciated. 
THE  REMOVAL  OR  DESTRUCTION  OF  TYPHOID  ORGANISMS  IN  FOOD 
AND  WATER. 
Heretofore  there  have  been  two  principal  methods  for  the  removal 
of  typhoid  organisms  from  drinking-water,  namely:  (i)  Filtration 
on  a  large  scale,  and  (2)  filtration  and  boiling  on  a  small  scale. 
Many  bio-chemical  methods  for  the  purification  of  water  have  been 
proposed,  some  of  which  may  be  enumerated : 
(1)  Aqua  regia  followed  by  sodium  carbonate. 
(2)  Bleaching  powder  followed  by  sodium  bicarbonate. 
(3)  Various  permanganates,  as  potassium,  calcium,  aluminum,  or 
barium. 
(4)  Perchloric  acid. 
(5)  Bromine  followed  by  ammonia. 
(6)  Iron  chloride  and  sodium  carbonate. 
(7)  Sodium  bisulphate. 
(8)  Peroxide  of  chlorine. 
{9)  Kerosene. 
(10)  Silver  salts. 
(11)  The  alum  process  has  been  used  for  purifying  the  water  sup- 
plies of  large  cities. 
1  The  Virginia  Medical  Semi- Monthly ;  February  12,  1904,  p.  501. 
