AmAigU,ri879ann'}   Linimentum  Terebinthin*  Aceticum.  417 
fection  of  this  mixture  is,  that  separation  begins  as  soon  as  shaking  has 
ceased.  Of  course,  no  other  result  could  be  expected  from  such  ingre- 
dients, and  in  the  original  formula  for  St.  John  Long's  celebrated  lini- 
ment, of  which  the  British  Pharmacopoeia  preparation  is  an  imitation, 
the  yolk  of  egg  was  used  to  form  an  emulsion.  There  would,  how- 
ever, be  some  objection  to  this  emulsifying  agent  in  an  application  which 
is  intended  to  be  rubbed  on  the  skin,  and  gum  or  mucilage,  the  ordi- 
nary means  of  forming  emulsions,  would  also  not  be  suitable  on  account 
of  their  stickiness.  It  is,  however,  possible  to  render  this  liniment 
perfectly  smooth  and  creamy,  and  one  which,  upon  evaporation,  leaves 
no  solid  matter  like  the  yolk  of  an  egg  or  mucilage.  The  agent 
employed  is  a  tincture  prepared  from  the  bark  of  the  Quillaia  saponaria. 
The  use  of  this  tincture  in  the  formation  of  emulsions  of  oils  and 
resins  is  by  no  means  a  new  one  ;  for  in  V  Union  Medicale  for  185 1  is 
an  article  by  Le  Beuf  on  the  use  of  this  tincture  for  making  emulsions, 
and  Le  Beuf  made  and  advertised  coal  tar  saponine,  emulsion  de  baume 
de  tolu  and  emulsion  de  goudron  vegetal.  It  does  not  appear  to  me  to 
have  come  into  use  in  English  pharmacy,  but  is  really  a  valuable  agent 
worthy  of  a  place  in  it.  It  is  in  constant  use  at  Guy's  Hospital  for 
the  preparation  of  emulsions,  and  in  the  new  Pharmacopoeia  of  that 
Hospital,  which  will  appear  in  a  few  weeks'  time,  a  formula  is  inserted 
for  preparing  the  tincture,  which  is  an  ingredient  in  some  of  the  hos- 
pital mixtures.  In  the  "  Rapport  sur  les  Medicaments  Nouveaux,"  1 
published  by  the  Paris  Society  of  Pharmacy,  tincture  of  quillaia  is  intro- 
duced for  the  "  emulsion  des  medicaments  insolubles  dans  l'eau."  I 
make  the  tincture  by  digesting  4  ounces  of  quillaia  bark,  coarsely  pow- 
dered, in  spt.  vini  rect.  Oj  (imper.)  for  four  days,  and  then  filtering.  3ss  of 
this  tincture  emulsifies  perfectly  3ss  of  a  fixed  oil  such  as  ol.  morrhuae 
with  oSS  of  water.  It  appears  to  me  from  the  results  of  my  experi- 
ments that  it  is  more  suited  for  fixed  and  volatile  oils  than  for  resins. 
I  hope,  however,  at  some  future  time,  to  be  able  to  state  precisely  the 
use  of  tinct.  quillaia  as  an  emulsifying  agent. 
To  return  to  linimentum  terebinthinae  aceticum.  The  following 
formula  gives  a  creamy  emulsion,  which  is  permanent  for  at  least  six 
minutes  after  shaking,  and  which  slowly  separates  into  three  layers,  a 
1  See  Pharmaceutical  Journal  [3],  vol.  viii.,  p.  26.  Amer.  Jour.  Pharm.,  1877,  P- 
348. 
*7 
