"Vor.rso""-}  Emulsions.  563 
Dissolve  the  resin  in  the  spirit,  add  the  powdered  gum  and  mix  well, 
add  now  an  ounce  of  water,  stirring  till  the  emulsion  is  formed  ;  make 
up  to  6  ounces  with  water. 
Emulsion  of  Balsam  of  Peru. 
Balsam  of  Peru,  ...  3  drachms 
Powdered  gum  acacia,  .  .  .        2  " 
Simple  syrup,      •  .  .  .  6  " 
Water,  .  ,  .  .  to  6  ounces. 
Rub  the  powder  well  with  the  balsam,  add  3  drachms  of  water  and 
stir  till  the  emulsion  is  perfect,  then  add  the  remaining  water  and 
syrup. 
In  emulsions  containing  resins  or  bodies  heavier  than  water  there  is 
generally  a  sediment  formed  ;  it  is  so  with  the  two  previous  forms,  but 
there  is  no  aggregation  into  a  hardened  mass,  and  a  slight  shake  of  the 
bottle  puts  all  right  again. 
Emulsion  of  Chian  Turpentine . 
Chian  turpentine,  .  .  .        2  drachms. 
Ether,  .  .  .  .  4 
Powdered  gum  acacia,  .  .  .        2  *' 
Water,  .  .  .  .  to  6  ounces. 
Dissolve  the  turpentine  in  the  ether  and  filter,  washing  the  filter 
with  a  drachm  of  ether,  mix  well  with  the  gum  and  add  \  ounce  of 
water,  stirring  till  the  emulsion  is  perfect,  lastly  add  the  remaining 
water. 
Attention  has  already  been  called  to  the  superiority  of  acacia  over 
tragacanth  to  emulsify  Chian  turpentine,  and  the  statement  cannot  be 
disproved. 
Many  of  these  forms  have  been  well  tested  and  practically  made  by 
large  classes  of  students,  and  the  results  have  been  most  satisfactory. 
Before  leaving  the  subject  I  will  sav  that  no  rule  of  thumb  practice 
should  be  attempted  in  making  an  emulsion  ;  success  may  occassionally 
occur,  but  annoyance  and  waste  of  time  and  material  is  the  invariable 
result. 
In  conclusion,  powdered  gum  acacia  in  my  hands  has  achieved  the 
greatest  success,  and  so  far  as  I  am  concerned  merits  the  distinction  of 
being  called  the  perfection  of  em  ilsifying  agents. — Pharm.  Jour,  aud 
Trans. ^  October  2,  1880. 
