70 
THERAPEUTIC  EFFECTS  OF  CARBONIC  ACID. 
feel  no  pain,  and  to  find  that  he  was  able  to  walk  without  his 
crutch.  He  continued  this  treatment  for  some  time,  and  has 
since  experienced  no  return  of  his  complaint. 
There  are  now  in  Germany  special  establishments  for  baths, 
douches,  and  the  inhalation  of  carbonic  acid.  According  to  M. 
Herpin,  the  first  effect  of  exposure  to  the  gas  is  a  sensation  of 
pleasant  heat,  like  that  from  a  garment  of  fine  wool — then  a 
pricking,  and  afterwards  a  burning  which  has  been  compared  to 
that  from  mustard. 
On  the  occasion  of  this  communication,  M.  Boussingault  related 
how  he  happened  in  1826  to  witness  some  of  the  effects  men- 
tioned by  M.  Herpin.  He  was  visiting  in  the  Quindiu,  New 
Grenada,  a  part  of  the  Cordillera,  some  solfataras,  where  nu- 
merous workmen  were  occupied  melting  and  purifying  sulphur. 
He  encountered  a  crevice  whence  issued  abundantly  a  gas  of  the 
odor  of  sulphuretted  hydrogen.  He  attempted  to  descend  in  it 
in  order  to  ascertain  the  temperature;  but  he  had  hardly  entered 
the  crevice  when  he  felt  a  suffocating  heat,  which  he  estimated 
at  40°  C.,and  a  pricking  in  the  eyes;  respiration  being  difficult, 
he  ascended  quickly  ;  his  face  was  red  and  his  perspiration 
abundant.  After  awhile  he  descended  again  with  his  thermome- 
ter, and  was  surprised  to  find  a  temperature  of  only  18^°  C. 
The  extreme  temperature  was  22°  C.  The  gas  was  composed 
of  95  per  cent,  of  carbonic  acid  and  5  p.  c.  of  atmospheric  air 
and  sulphuretted  hydrogen.  It  was  hence  the  carbonic  acid 
which  caused  the  sensation  of  heat  and  the  irritation  of  the  eyes. 
At  two  other  times,  in  1827  and  1830,  M.  Boussingault  ex- 
perienced again  the  same  sensations.  He  observed  that  the 
workmen  who  work  long  in  the  solfataras  of  the  Cordillera,  in 
contact  with  the  carbonic  acid,  experience  an  enfeebling  of  the 
sight,  and  some  of  them  become  blind. 
Dr.  Herpin  confirmed  the  fact  with  regard  to  the  action  of  on 
the  eyes  of  the  baths  of  gaseous  carbonic  acid.  He  observed  that 
the  douches  of  carbonic  acid  had  been  used  against  "  amblyopia," 
or  enfeebling  of  vision,  and  different  precautions  were  used 
to  moderate  the  effects  of  the  gas  or  diminishing  the  force  of  the 
jet,  or  its  distance  ;  or  its  direct  action  by  interposing  muslin. 
When  the  eyes  have  an  inflammatory  tendency,  it  irritates  the 
organ,  and  even  the  neighboring  parts  ;  the  heat  sometimes  pro- 
duces dangerous  congestion. — Sillimaris  Journal,  Sept.,  1855. 
