290 
Emulsions. 
Am.  Jour.  Pliarra. 
June,  1881. 
ble  quantity  of  alcohol  or  olive  oil  and  then  treating  it  as  belonging 
'  to  Class  1^  or  by  rubbing  one  part  very  finely  pulverized  camphor 
with  ten  parts  of  guin  arable  and  sugar,  and  then  adding  water  grad- 
ually. * 
Under  this  class  might  yet  be  mentioned  an  emulsion  of  phosphorus. 
This  is  dissolved  in  a  mucilage  of  gum  arable  with  the  aid  of  heat, 
and  is  then  easily  divided.    It  would,  however,  be  much  more  proper 
to  administer  this  powerful  drug  by  emulsifying  oleum  phosphoratum. 
Class  o.  Emulsions  of  gum-resins. 
These  preparations,  of  which  a  few  are  officinal  m  the  IT.  S.  P. 
under  the  name  of  misturie,  are  made  by  simply  rubbing  the  gum- 
resin  reduced  to  a  fine  powder  with  water,  and  in  this  way  bringing 
them  back  again  to  the  state  of  milky  plant-juices,  as  which  they  were 
obtained  from  nature.  The  vegetable  albumen  or  gum  contained  in 
the  gum-resins  serves  as  binding  medium.  The  only  difficulty  in 
making  those  preparations  is  the  reducing  of  the  gum-resins  to  a  fine 
powder.  By  placing  the  mortar  in  a  hot  water  bath,  this  operation 
will  be  greatly  facilitated.  After  a  very  fine  powder  has  been  obtained, 
the  water  is  added  in  small  qnantities  at  a  time,  beating  the  mass  at 
first  and  then  stirring,  after  more  water  has  been  added,  very  briskly, 
levigating  the  finest  particles,  and  repeating  this  operation  until  noth- 
ing or  only  impurities  are  left.  In  order  to  prevent  the  evaporation 
of  volatile  oils  which  the  resins  may  contain,  on  placing  them  in  a  hot 
water  bath,  it  is  well  to  sprinkle  a  little  water  over  them. 
Some  pharmacists  are  in  the  habit  of  beating  the  gum-resin  with 
gum  arable  in  pieces,  which  is,  however,  not  necessary  and  inadmis- 
sible unless  the  physician  or  the  Pharmacopoeia  directs  this  addition. 
Class  4.  Emulsions  of  resins. 
This  class  of  preparations  differs  from  the  foregoing  only  by  the 
fact  that  they  cannot  be  made  without  the  addition  of  a  binding 
medium.  They  are  treated  in  the  same  manner  as  gum-resins,  after 
liaving  mixed  half  a  })art  of  gum  arable  with  the  finely  powdered 
resin.  Pesina  jalap^e  and  resina  scammonii  cannot  be  rendered  misci- 
ble  with  water  by  means  of  gum  arabic  except  by  using  from  10  to 
20  parts  of  the  latter.  A  much  better  plan  is  to  beat  the  resins  into  a 
pulpy  mass  with  a  few  sweet  almonds,  deprived  of  their  skins  "  via 
frigida,"  and  diluting  with  water. 
Class  5.  Emulsions  of  seeds. 
They  are  made  from  seeds  and  friuts  containing  large  quantities  of 
