PREPARATION  OF  EMPLASTRUM  ASSAFCETID^E.  533 
ON  THE  PREPARATION  OF  EMPLASTRUM  ASSAFCETIDiE. 
By  William  Procter,  Jr.,  of  Philadelphia. 
(From  the  Proceedings  of  the  American  Pharmaceutical  Association — 1860.) 
The  following  remarks  are  in  reply  to  the  tenth  query  of  the 
list  of  questions  offered  at  the  meeting  of  1859,  viz  : — 
"  What  is  the  best  process  for  preparing  Assafoetidse  Plaster  so  as  to 
preserve  the  activity  of  the  drugs  unimpaired?  " 
The  present  process  for  this  plaster  (U.  S.  P.)  is  as  follows  : — 
"Take  of  Assafetida,  Lead- plaster,  each  a  pound. 
Galbanum,  Yellow-wax,  each  half  a  pound. 
Alcohol,  three  pints. 
Dissolve  the  assafetida  and  galbanum  in  the  alcohol  by  the 
aid  of  a  water  bath ;  strain  the  liquor  while  hot,  and  evaporate 
to  the  consistence  of  honey  ;  then  add  the  lead-plaster  and  wax, 
previously  melted  together ;  stir  the  mixture  well,  and  evaporate 
to  the  proper  consistence." 
Theoretically,  about  two-thirds  of  the  weight  of  assafetida 
is  soluble  in  alcohol ;  practically,  even  with  the  aid  of  heat,  the 
residue  is  quite  bulky,  even  when  the  gum-resin  is  malaxated 
in  a  mortar  with  the  solvent ;  and  the  tears  are  difficult  to 
disintegrate  without  that  precaution.  If  this  residue  is  separated 
and  washed  with  alcohol,  and  the  alcoholic  liquid  evaporated 
with  care,  and  incorporated  with  the  melted  ingredients  as 
directed,  a  good  plaster  results.  The  objections  to  the  process 
are  the  slow  action  of  alcohol,  and  the  greater  or  less  loss  of 
volatile  oil  by  the  evaporation,  if  at  the  temperature  of  the 
water-bath.  In  view  of  these  objections  the  use  of  other  solvents 
has  been  suggested.  A  priori,  benzine,  so  noted  for  its  solvent 
action  on  resinous  bodies,  was  supposed  to  be  a  cheap  and 
appropriate  menstruum,  and  was  tried,  but  found  to  be  entirely 
inapplicable,  as  its  solvent  action  was  very  slow,  hardly 
altering  the  shape  of  the  particles  or  fragments.  Chloroform 
was  next  used  with  entire  success ;  it  rapidly  broke  down  the 
gum-resin,  dissolving  all  its  oily  and  resinous  matter  and  leaving 
the  gum  as  a  flocculent  powder.  The  proportion  tried  was  two 
parts,  by  weight,  to  one  of  the  resins,  which  were  operated  on 
separately  to  ascertain  the  relative  solvency  in  the  menstruum, 
and  they  were  found  equally  affected  by  it. 
Ether  was  then  tried  and  found  to  greatly  exceed  alcohol  in 
its  ability  quickly  to  dissolve  out  the  resinous  matter  from  the 
