EMULSIONS  OF  GUM-RESINS  AND  RESINS. 
61 
nitric  ether  can  be  separated  by  agitation  with  a  solution  of 
chloride  of  calcium.  From  48  ounces  of  spirit  of  wine  8  ounces 
of  nitric  ether  may  be  separated  in  this  way,  which  rectified  over 
dry  chloride  of  calcium  will  give  pure  nitric  ether.  The  yellow 
color  depends  upon  a  body  mixed  with  the  ether,  which  cannot 
be  removed  by  rectification  over  sugar,  as  stated  by  Couerbe,  but 
a  portion  may  be  obtained  colorless  by  fractional  distillation. 
The  ether  of  specific  gravity  .898  begins  to  boil  at  63.5°  Fahr., 
and  boils  completely  at  64.4°.  Nitric  ether  is  the  only  ether 
which  is  obtained  considerably  in  a  diluted  watery  fluid,  and  the 
only  one  which  is  not  formed  in  a  concentrated  fluid,  by  the 
power  of  muriatic  acid  or  sulphuric  acid  to  abstract  water,  and, 
moreover,  the  only  one  which  results  by  a  decomposition  of  its 
acid,  and  simultaneously  with  the  oxidation  of  the  alcohol.  The 
latter  abnormity  does  not  happen  when  nitrous  acid,  instead  of 
nitric  acid,  is  directly  employed.  Nitric  ether  prepared  accord- 
ing to  Kopp's  method,  and  the  previously  known  ones,  always 
contains  aldehyde.  By  its  decomposition  with  caustic  potash  or 
soda  this  liquid  acquires  a  brown  red  color.  Nitrous  ether  can 
be  kept  for  months  in  contact  with  potash,  without  undergoing 
decomposition ;  but  the  author  has  again  obtained  the  alcohol  by 
the  treatment  of  this  ether  with  potash  ley  in  closed  tubes ; 
nevertheless,  he  infers  that  it  cannot  be  regarded  as  the  nitrate 
of  ethyl-oxide,  but  must  be  considered  as  NC4  H5  04. — Annals  of 
Pharmacy,  from  Buchners  Repertorium. 
ON  EMULSIONS  OF  THE  GUM-RESINS  AND  RESINS. 
By   M.  CONSTANTIN. 
Up  to  the  present  time  the  gum-resins  and  resins  have  been 
but  rarely  employed,  on  account  of  the  difficulty  of  -mixing  them 
with  liquids  for  administration.  The  purification  of  these  substan- 
ces, even  by  means  of  vinegar  or  alcohol,  has  been  rejected  ;  for, 
as  Lemery  very  justly  remarks,  it  is  preferable  to  choose  gum- 
resins  and  resins  free  from  impurities,  than  to  purify  them  by  any 
means  whatever.  In  Pharmacy  we  have  only  the  alcoholic  solu- 
tions of  gum  ammoniacum  and  assafoetida,  and  the  alcoholic  and 
ethereal  solutions  of  tolu,  which  substances  I  have  most  carefully 
examined,  and  all  of  which,  when  added  to  an  aqueous  liquid,  very 
