DISINFECTION  OF  NITROGENOUS  MANURE. 
143 
night  soil  percolate  the  earth  underlying  all  our  cities.  These 
matters  washed  forward  by  the  rains,  diffuse  the  products  of  pu- 
trefaction every  where  ;  then  the  heat  of  summer,  by  evapora- 
tion at  the  surface,  may  bring  poisonous  effluvia  up  from  the 
whole  area  of  the  city.  The  water  of  our  wells,  as  is  known, 
are  impregnated  with  these  products.  Not  long  since  an  intel- 
ligent citizen  requested  me  to  make  a  chemical  examination  of 
the  water  of  a  well  wThich  was  formerly  very  good,  but*was  now 
strongly  flavored,  and  by  several  persons  it  was  thought  to  have 
the  taste  of  a  chalybeate  water.  Upon  testing,  the  water  was 
found  to  have  imbibed  rather  freely  from  the  privy  products  of 
the  neighborhood  !    Such  wells  are  common. 
Not  only  does  public  health  demand  that  this  grievous  nuisance 
should  at  once  be  abated,  especially  as  the  requisite  means  are 
simple  and  well  known,  but  agriculture  seconds  this  demand,  in-, 
as  much  as  night-soil  is  valuable  as  manure,  particularly  when 
treated  so  as  to  retain  all  the  nitrogen,  most  of  which  is  liable  to 
escape  in  the  ammonia  which  is  generated  during  the  process  of 
putrefaction.  Indeed  it  contains  all  the  elements  derived  from 
the  soil  by  vegetation,  and  hence  is  an  excellent  fertilizer. 
The  reform  in  Paris,  to  which  allusion  has  been  made,  was  ef- 
fected by  the  Soci^te  d'Agriculture  and  the  Society  d'Encou- 
ragement  pour  1'Industrie  Nationale,  and  in  the  United  States 
we  may  expect  reform  from  the  exertions  of  agriculturists 
rather  than  from  those  of  sanitary  officers. 
One  general  criticism  may  be  applied  to  the  means  commonly 
recommended  for  disinfecting  and  deodorizing  privies,  sewers, 
and  gutters.  The  methods  proposed  do  not  meet  all  the  chemi- 
cal conditions  ;  they  attempt  too  much  with  a  single  reagent.  In 
night-soil  many  elements  occur,  forming  various  compounds,  or- 
ganic and  inorganic,  some  acid,  some  alkaline  or  basic,  some 
united  as  fixed  salts,  others  becoming  gaseous,  and  tending  to 
escape  into  the  atmosphere.  Among  the  gaseous  products  are 
sulphydric  acid,  carbonic  acid,  ammonia,  or  carbonate  of  ammo- 
nia, together  with  various  exhalations  not  yet  investigated.  But 
the  quantity  of  some  cf  these  is  so  inconsiderable  as  to  require 
little  attention.  Now,  in  order  to  completely  deodorize  and 
disinfect  night-soil,  it  is  necessary  to  add  such  different  chemical 
reagents  as  will  unite  with  each  of  these'gases,  converting  them 
