214  Dr.  white’s  Experiments 
bably  aft  as  an  antifeptic  upon  the  dead  one.  Fixed  air 
is  a powerful  antifeptic  in  the  one,  hut  is  deadly  to  the 
other.  Nitrous  air  preferves  all  flefh  from  corruption 
after  death ; yet  let  any  living  animal  but  once  breathe  in 
it,  and  it  inftantly  expires.  Some  of  our  bogs  have  the 
lingular  property  of  preferving  dead  bodies  not  only 
fweet  but  pliable  for  many  years ; but  we  are  certain  they 
are  at  the  fame  time  deadly  to  living  animals. 
exp.  xxii.  A fourth  part  of  an  eight-ounce  phial  was 
filled  with  the  fame  mud  as  in  the  laft  experiment,  but 
fo  much  dried  in  the  fun  as  to  be  eafily  rubbed  into  a 
powder,  the  reft  being  air;  after  being  corked,  they  were 
fet  by  for  twenty-four  hours,  and  in  the  interim  fre- 
quently agitated.  The  air  being  at  the  end  put  to  the 
teft  was  fcarcely  altered,  the  greateft  diminution  in  feve- 
ral  different  experiments  was  only  from  62°  to  6o°.  So 
that  the  air  was  yet  quite  good,  although  they  flood  dou- 
ble the  time  of  that  in  the  laft  experiment. 
Hence  it  is  evident,  that  bogs  and  marlhy  grounds, 
when  dry,  or  perfectly  drained  of  their  moifture,  become 
healthy,  and  emit  no  noxious  exhalations. 
This  illuftrates  the  obfervation,  that  fuch  fituations 
are  not  liable  to  produce  their  peculiar  difeafes  during 
the  dry  feafons,  or  after  being  well  drained.  And  it  is 
obferved,  that  in  the  moft  unhealthy  of  our  fettlements 
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