182 
Emulsions. 
/  Am.  Jotir.  Phann^ 
t      April,  1882. 
proportion  to  each  other.  Tliis  pro])ortIon  is  three  (3)  parts  of  water 
to  two  ^)  parts  of  gum,  both  by  weight. 
2.  That  the  relation  of  oil  to  gum  (and  water)  shall  be  definite 
within  certain  limits ;  that  is  to  say,  the  mucilage  formed  in  the  above 
proportions  is  capable  of  perfectly  emulsifying  a  minimum  and  a  max- 
imum proportion  of  oil.  The  minimum  proportion  is  two  (2)  parts  of 
oil  to  one  (1)  part  of  gum;  the  maximum  proportion  is  four  (4)  parts^ 
of  oil  to  one  (1)  part  of  gum. 
8.  That  the  trituration  of  the  oil,  gum  and  water  be  continued. till, 
a  perfectly  homogeneous,  milky-Avhite,  thick-creamy  mixture  is  formed 
— 6.,  until  perfect  emulsification  takes  place — before  the  addition  of 
a  further  quantity  of  water  or  other  liquid. 
The  thick  creamy  emulsion  obtained,  if  the  above  conditions  are 
fulfilled,  must  be  the  basis  of  all  perfect  emulsions.  It  will  bear  dilu- 
tion to  any  extent  with  water,  forming  mixtures  varying,  according  to 
the  proportion  added,  from  the  appearance  and  consistence  of  cream  to 
that  of  very  thin  milk.  Obviously  the  water  may  be  substituted  by 
solutions  of  saline  compounds,  syrups,  etc.,  and  this  enables  the  pro- 
duction of  the  various  combinations  of  codliver  oil  in  current  use^ 
from  the  above  thick-creamy  emulsion,  which  for  distinction  I  shall 
designate  as 
I.  Concentrated  Ew.ulsion  of  Codliver  Oil.  Take  of  fresh  Norwe- 
gian codliver  oil  eight  (8)  troyounces;  powdered  gum  arable,  two  (2^ 
troyouncee;  distilled  water,  three  (3)  troyounces.  First  weigh  the 
gum  into  a  wedgewood  or  porcelain  mortar,  then  the  oil,  and  triturate 
till  the  gum  is  well  mixed  with  the  oil ;  then  weigh  into  the  mixture 
the  distilled  water,  and  triturate  the  whole  briskly  until  the  mixture 
thickens  and  acquires  a  pasty  consistence  and  milky  whiteness.  Now 
scrape  down  the  portions  adhering  to  the  sides  of  the  mortar  and  to  the 
pestle,  and  continue  the  trituration  for  a  short  time,  after  which  add 
such  other  ingredients  as  may  be  desirable  or  transfer  the  concentrated 
emulsion  to  a  wide-mouthed  bottle  for  future  use. 
This  concentrated  emulsion  will  keep  for  a  reasonable  time  in  cold 
weather,  and,  if  placed  in  the  ice  chest,  also  during  warm  weather.  It 
may  therefore  be  kept  in  stock  if  the  demand  for  emulsions  is  brisk 
enougli  to  justify  it;  but  inasmuch  as  its  preparation  does  not  consume 
more  than  five  or  ten  minutes,  it  is  advised  to  always  prepare  it  fresh,, 
or,  at  all  events,  never  to  prepare  more  than  a  week's  supply,  particu- 
larly in  summer.    Its  consistence  is  such  that  it  is  poured  out  of  the 
