DISINFECTING  PROPERTIES  OF  CHARCOAL,  SAND,  ETC.  519 
measures  which  have  been  adopted  for  the  benefit  of  our  army  in 
the  Crimea,  in  which  allusion  is  made  to  the  use  of  charcoal, 
lime,  sand,  and  gravel,  for  deodorizing  and  disinfecting  purposes. 
Our  attention  has  been  directed  to  this  letter  by  a  correspondent, 
who  thinks  Dr.  Sutherland  is  wrong  in  classing  sand  and  gravel 
with  charcoal  and  lime  for  the  purposes  specified.  He  enquires 
whether  the  action  of  sand  and  gravel  is  not  purely  mechanical, 
while  that  of  charcoal  and  lime  is  chemical.  The  subject  is  one 
of  considerable  interest  and  importance,  and  one  on  which  some 
difference  of  opinion  may  exist. 
Dr.  Sutherland  says,  they  use  three  deodorizing  substances — 
charcoal,  lime,  and  sand  or  gravel  ;  that  charcoal  acts  extremely 
well,  and  in  small  quantity ;  that  lime  also  acts  very  well ;  and 
that  sand  or  gravel,  for  certain  purposes,  is  as  good  as  either, 
but  that  a  large  quantity  of  this  is  required  to  produce  the  effect, 
and  therefore  its  use  is  limited  by  the  difficulty  of  carriage.  He 
further  states  that  any  one  of  these  substances  would,  he  believes, 
act  as  a  disinfectant,  if  a  proper  quantity  were  used.  Lastly, 
he  says  that  charcoal,  in  any  ordinary  quantity  is  not  a  disin- 
fectant. 
We  are  not  prepared  fully  to  adopt  this  opinion,  but  at  the 
same  time  we  do  not  think  it  is  subject  to  the  objection  urged  by 
our  correspondent.  There  is  reason  to  believe  that  a  substance 
may  act  completely  as  a  deodorizer  while  it  acts  but  imperfectly, 
if  at  all,  as  a  disinfectant.  Dr.  Sutherland  adduces  evidence  in 
confirmation  of  this  view.  He  says  that  a  ship  which  took  charcoal 
to  Balaklava,  having  occasion  to  lay  for  some  weeks  in  the  har- 
bor, close  to  the  wharf,  and  not  far  from  large  accumulations  of 
foul  matter,  had  several  cases  of  cholera  on  board,  although  the 
cargo  was  being  discharged,  and  the  men  and  every  part  of  the 
vessel  were  covered  with  the  dust  of  the  charcoal,  bags  of  which 
charcoal  were  piled  up  on  the  wharf  cose  to  the  vessel.  In  this  case, 
the  charcoal  completely  deodorized  but  did  not  disinfect  the  air  on 
board  the  vessel ;  and  to  get  rid  of  the  disease  it  was  found 
necessary  to  send  the  ship  out  of  the  harbor.  Dr.  Sutherland 
suggests  that  when  charcoal  is  used  in  the  ordinary  quantities 
for  deodorizing  purposes,  it  would  be  wise  not  to  apply  to  it  the 
term  "  disinfectant,"  as  it  might  lead  to  undue -expectations, 
and  cause  other  more  efficient  measures  for  disinfection  to  be 
neglected. 
