DISINFECTION  OF  NITROGENOUS  MANURE. 
145 
employ  only  2  p.  c.  of  the  volume  of  night-soil  to  decompose  all 
the  sulphydric  acid,  and  then  lime  and  its  sulphate  may  be  ad- 
ded to  neutralize  the  ammonia  and  carbonic  acid. 
Of  all  the  disinfectants  and  deodorizers  hitherto  employed  no 
substance  produces  more  remarkable  effects  than  fresh  charcoal 
in-a  pulverulent  state.  Its  antiputrescent  effects  were  discovered 
by  Lowitz  about  1790  ;  but  the  discovery  has  been  slowly  ap- 
plied. In  1829  Frigerio  proposed  to  employ  charcoal  for  pre- 
serving meat,  and  in  1836  he  published  in  the  Brevet  d'lnven- 
tion  an  account  of  a  safe,  consisting  of  a  double  screen  of  wire 
gauze  with  the  interspaces  filled  with  fresh  charcoal.  This  safe 
was  found  to  preserve  meat  in  the  hottest  weather  perfectly  sweet 
for  a  whole  week.  During  many  years  charcoal  has  been  (espe- 
cially in  Europe)  extensively  mixed  with  human  excrements,  for 
which  purpose  it  has  been  found  to  be  admirably  adapted,  not 
only  by  its  deodorizing  and.  disinfecting  qualities,  but  also  by  its 
being  itself  a  powerful  stimulant  to  the  growth  of  vegetation. 
The  experiments  of  Dr.  Stenhouse,  of  London,  prove  that  a 
carcass  covered  with  charcoal  powder  emits  no  unpleasant  odor 
during  its  entire  decomposition  ;  that  hospital  grangrene  and 
other  putrid  sores  are  arrested  by  the  use  of  charcoal.  He  sug- 
gests the  use  of  charcoal  air-filters  for  admission  of  air  to  apart- 
ments in  infected  districts,  and  charcoal  respirators  for  those  ex- 
posed to  infection.  He  thinks  the  charcoal  decomposes  effluvia 
by  simple  oxidation,  converting  their  carbon  into  carbonic  acid, 
their  hydrogen  into  water,  and  thus  hastening  decomposition, 
instead  of  being  antiseptic,  as  heretofore  supposed.  The  com- 
plete success  of  the  charcoal  screens  used  in  London  clearly  in- 
dicate the  propriety  of  using  charcoal  to  arrest  the  contagion  of 
yellow  fever.  During  the  recent  discussion  respecting  the  burn- 
ing of  bodies  a  lady  suggested  that  charcoal  be  strewn  freely 
into  the  grave  so  as  to  surround  the  coffin,  thus  completely  pre- 
venting the  escape  of  effluvia. 
For  the  last  twenty  years  chemists  have  been  employed  in  ap- 
plying their  science  to  the  manufacture  of  poudrette,  and  in 
investigating  the  'causes  of  insalubrity  connected  with  the  man- 
agement of  night-soil.  These  investigations,  conducted  in  dif- 
ferent countries,  have  required  such  varied  experiments  that  the 
labor  may  be  regarded  as  only  begun.    In  the  present  state  of 
10 
