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514  SPONTANEOUS  GENERATION  OF  PRUSSIC  ACID. 
Nor  did  it  present  itself  to  my  own  mind  until  recently.  I  think 
it  should  claim  the  notice  of  those  who  are  interested  in  the  treat- 
ment of  disease,  as  well  as  of  those  who  are  engaged  in  pharma- 
ceutic chemistry. 
The  short  train  of  events  leading  to  the  development  of  this  fact 
was  as  follows  : 
A  young  physician  applied  to  me  on  account  of  an  attack  of 
sickness  the  day  before,  for  which  he  could  assign  no  satisfactory 
reason.  He  said  that  while  he  was  engaged  in  reading,  he 
suddenly  became  unconscious,  and  remained  so  for  half  an  hour, 
according  to  the  statement  of  his  wife.  After  he  revived  suffi- 
ciently to  walk  about,  he  said  he  felt  half  bewildered,  and  found 
that  his  powers  of  recollection  were  greatly  impaired,  if,  indeed, 
they  were  not  sometimes  entirely  gone. 
He  could  not  attribute  it  to  anything  inhibited,  unless  it  was  a 
preparation  of  carbonate  of  potash  and  tincture  of  hyoscyamus 
which  a  distinguished  Eastern  pbvsician  had  prescribed  for  him,, 
and  which  he  had  repeatedly  taken  before,  without  any  ill  effect. 
As  the  patient  belonged  to  the  class  of  dyspeptics,  I  was  at  first 
inclined  to  attribute  his  attack  to  some  ordinary  gastric  derange- 
ment displaying  itself  upon  the  nervous  system ;  but  on  further  re- 
flection and  consultation  with  him,  I  learned  that  the  preparation 
of  which  he  took  the  dose  in  question,  (a  teaspoonful,)  was  one 
that  he  had  made  some  time  before  and  laid  aside. 
This  consideration  induced  me  to  make  a  chemical  examination 
of  the  contents  of  the  vial.  At  the  bottom  of  the  vessel  there  was 
a  copious,  pure  white,  delicate  deposit ;  the  supernatant  fluid  was 
clear,  and  had  a  suspicious  odor,  which  led  me  to  test  for  prussic 
acid.  There  was  a  perceptible  fermentation  going  on  in  the 
liquid. 
The  white  sediment  was  collected  on  a  filter,  washed  and  sub- 
jected to  the  action  of  acids,  and  also  to  the  red  heat  of  a  platinum 
spoon.  But  none  of  these  agents  produced  any  sensible  impression 
upon  it.  I  then  exposed  it  to  the  heat  of  a  blow-pipe  flame,  with 
carbonate  of  soda,  and  obtained,  what  I  anticipated, — silicate  of 
soda.  The  silica  was  probably  derived  as  an  impurity  from  the 
carbonate  of  potash,  which  entered  into  the  composition  of  the 
medicine. 
The  filtrate  was  received  into  a"  wide-mouthed  vial ;  and  the 
