THERAPEUTIC  EFFECTS  OF  CARBONIC  ACID.  69 
periments,  I  found  in  saponification  the  means  of  detecting  the 
nature  of  the  fraudulent  admixture.  When  acted  upon  by  a 
caustic  alkali,  the  oil  deposited  a  small  portion  of  sulphur, 
which  blackened  immediately  the  silver  basin  which  I  used  in  the 
operation.  This  circumstance  caused  me  at  once  to  suspect  that 
the  oil  used  for  adulteration  was  derived  from  a  cruciferous  seed. 
I  treated  all  the  commercial  fatty  oils  with  a  solution  of  pure 
caustic  potash,  and  I  had  the  satisfaction  to  see,  that  all  the  cru- 
ciferous oils  yielded  a  quantity  of  sulphur,  which  in  the  state  of 
alkaline  sulphuret  formed  in  the  process,  was  quite  sufficient  to 
be  detected  by  the  usual  reagents — as  lead  or  silver,  salts,  &c* 
All  the  other  oils,  as  linseed,  poppy,  nut  oil,  could  be  treated  in 
the  same  way  without  any  indication  of  the  presence  of  sulphur. 
I  propose,  therefore,  the  following  as  a  test  for  an  oil  of  the 
cruciferas — such  as  colza,  rape,  mustard,  &c,  in  other  oils. 
Twenty-five  to  thirty  grammes  (seven  to  eight  drachms)  of  the 
suspected  oil  are  boiled  in  a  porcelain  basin,  with  a  solution  of 
thirty  grains  of  pure  caustic  potash  in  five  drachms  of  distilled 
water.  After  an  ebullition  of  a  few  minutes  the  whole  is  filtered, 
and  the  filtrate,  when  tested  with  nitrate  of  silver  or  acetate  of 
of  lead  paper,  will  speedily  indicate  the  presence  of  sulphur. 
If,  instead  of  a  porcelain  capsule,  the  oil  is  saponified  in  a  silver 
vessel,  the  blackening  of  the  latter  speedily  becomes  visible.  This 
test  is  very  prompt  and  delicate,  indicating  the  presence  of  one 
hundredth  part  of  a  cruciferous  oil  in  any  other  oil. — Pharm. 
Joarn.y  from  Comptes  Jlendus. 
PHYSIOLOGICAL  AND  THERAPEUTIC  EFFECTS  OF  CARBONIC 
ACID. 
Some  weeks  since  M.  Herpin,  of  Metz,  stated  the  following 
facts  to  the  Academy.  Dr,  Struve  took  the  Marienbad  waters 
for  a  painful  affection  of  the  leg.  He  had  been  unable  for  several 
weeks  to  walk  without  a  crutch.  Dr.  Struve  had  the  notion  one 
day  of  exposing  his  leg  to  the  action  of  the  carbonic  acid  which 
escapes  freely  from  the  spring  at  Marienbad,  and  forms  a  bed 
several  decimeters  deep  over  its  surface.  After  exposure  for  a 
while  it  produced  a  pricking  sensation  and  warmth,  which  went 
on  increasing  till  it  occasioned  a  profuse  perspiration  of  the  dis- 
eased limb.    On  withdrawing  then  his  leg,  he  was  surprised  to 
