DECOLORIZING  PROPERTY  OF  THE  ESSENTIAL  OILS. 
401 
It  appears  to  me  that  this  reaction  of  the  oils  upon  An02  S03, 
may  be  profitably  appropriated  in  Pharmacy.  For  example  :  Oil 
of  Savine  is  liable  to  be  adulterated.  I  find  on  testing  it  with 
An02  S03,  that  the  blue  color  is  not  discharged  except  by  a  large 
quantity  of  the  oil ;  and  to  effect  the  bleaching  quickly,  heat  is  re- 
quired ;  and  further,  that  the  oil  remains  clear. 
On  the  other  hand,  the  oils  of  juniper,  fir,  and  hemlock,  (the  ar- 
ticles most  likely  to  be  chosen  to  adulterate  the  oil  of  savine,) 
bleach  a  very  large  proportion  of  the  blue  liquid.  It  is  done 
quickly,  heat  is  not  required,  and  the  oils  become  milky. 
Black  and  White  Mustard* 
Sinapis  nigra  yielding  a  volatile  oil  belonging  to  the  third  class, 
and  Sinapis  alba,  according  to  our  authors,  furnishing  no  essential 
oil,  it  became  an  interesting  question  to  know  what  effect  the  two 
species  of  seeds  would  produce  upon  An2  S03. 
One  scruple  each  of  sound  black  and  white  mustard  seed  was 
triturated  to  the  same  degree  of  fineness,  and  emptied  into  equal 
portions  (test  tubes  nearly  full)  of  the  blue  solution.  Both  por- 
tions of  the  liquid  were  instantly  affected.  The  contents  of  the 
tubes  wTere  shaken  together,  and  then  filtered.  The  filtrate  of  the 
black  mustard  mixture  was  of  a  very  pale  yellowish-green  color ; 
that  of  the  white  mustard  of  a  very  pale  pea-green  color.  These 
[In  reflecting  on  the  curious  results  detailed  by  Dr.  Plummer,  it  has  oc- 
curred to  us  that  probably  the  bleaching  power  was  due  to  ozone.  Faraday 
has  stated  (Lecture  at  Royal  Inst.,  noticed  in  Lond.  Med.  Gaz.,  June  20th, 
1851,  and  copied  into  Amer.  Jour,  of  Pharm.,  vol.  xxiv,  p.  74,)  that  "  Essen- 
tial Oils  are  thickened  by  long  exposure  to  light  and  air ;  they  become 
ozonized,  and  their  properties  changed.  This  was  illustrated  by  reference 
to  oil  of  turpentine.  Freshly  rectified  and  pure  oil  of  turpentine  was  proved 
by  admixture  with  sulphate  of  indigo  to  have  no  bleaching  power.  A  small 
quantity  of  oil  which  had  been  exposed  to  air  and  light,  (in  a  bottle  half 
full,)  destroyed  the  color  in  a  few  minutes  like  chlorine."  It  is  probable 
that  the  oils  tried  by  Dr.  P.  were  those  in  the  shop  bottle.  Could  not  the 
air  in  the  test  tube,  in  the  experiment  with  camphine  vapor,  have  become 
ozonized,and  this  acting  powerfully  as  stated  on  the  sulph-indigotic  solution? 
The  facilitating  influence  of  the  sun's  rays  in  the  camphor  experiments  is 
an  additional  reason  in  favor  of  this  supposition.  We  have  not  had  time 
to  compare  experimentally  the  results  of  Dr.  Plummer  with  the  views  of 
Faraday,  but  have  thought  best  to  throw  out  the  suggestion. — Editor  Am. 
Journ.  Pharm.] 
28 
