jim.  Jour.  Pharm. 
April,  1888. 
Oil  of  Pennyroyal. 
165 
Analysis  oj  the  Adds. — About  1 50  grams  of  the  original  oil  were 
repeatedly  shaken  Avith  water^  until  the  separated  water  had  a  neutral 
reaction,  this  was  marked  X^,  and  set  aside  for  further  examination. 
The  oil  was  then  shaken  with  lime-water  to  take  out  any  remaining 
acid,  until  after  filtering,  the  oil  had  a  neutral  reaction.  A  portion  of 
it  was  placed  in  a  flask  connected  with  an  upright  condenser,  the  top 
of  which  was  connected  with  a  piece  of  glass  tubing  so  that  the  end 
<iipped  beneath  the  surface  of  water,  contained  in  a  test-tube,  so  as  to 
absorb  any  volatile  substance  which  might  possibly  not  have  been  con- 
densed. After  taking  this  precaution  the  oil  was  actively  boiled  for 
three  hours.  The  w^ater  in  the  test-tube  was  then  tested  and  found  to 
be  neutral.  Water  was  next  poured  into  the  condenser,  to  wash  down 
any  remaining  substance  into  the  flask  containing  the  oil,  and  the  flask 
was  well  shaken ;  the  oil  and  water  separated,  both  giving  neutral  re- 
actions with  test  paper. 
The  remaining  portion  of  the  oil  was  distilled ;  all  of  the  distillates 
obtained  at  different  temperatures,  gave  a  neutral  reaction,  when  tested 
with  test  paper,  thus  showing  that  no  acid  is  liberatedby  the  decompo- 
sition of  a  compound  ether  in  the  oil,  on  boiling  or  distilling,  but  that 
all  of  the  acid  present  is  in  a  free  state. 
Portion  X. — This  acid  solution  was  treated  with  barium  carbonate 
in  excess,  filtered  and  evaporated  over  sulphuric  acid ;  a  sticky  mass 
and  only  a  few  crystals  were  obtained.  This  was  dissolved  in  water, 
filtered  from  the  excess  of  barium  carbonate,  and  the  filtrate  evapo- 
rated to  dryness  on  a  water-bath,  when  a  large  quantity  of  crystals 
was  obtained  which  were  again  dissolved  in  water ;  on  evaporating 
the  solution  over  sulphuric  acid  again  a  sticky  mass  was  left.  This 
was  dissolved  and  gdis  e  the  following  reactions  : 
I.  With  solution  of  ferric  chloride  a  bright-red  color  was  produced, 
which,  on  heating,  gave  a  slight  precipitate. 
II.  With  solution  of  silver  nitrate  a  white  precipitate,  which,  on 
slightly  heating,  was  soon  reduced. 
III.  With  solution  of  mercuric  chloride  a  white  precipitate,  re- 
duced, when  heated  for  some  time. 
IV.  When  heated  gently  with  sulphuric  acid  and  alcohol,  an  odor 
resembling  formic  ether  was  produced. 
These  all  seem  to  show  the  presence  of  a  formate,  especially  reac- 
tions III.  and  IV.  Reactions  I.  and  II.  may  have  been  partly  caused 
by  an  acetate,  as  will  be  seen  by  the  following  experiments : 
