490 
TEST  FOR  OTTO  OF  ROSES. 
The  oil  is  often  taken  in  the  form  of  an  emulsion.  1  oz.  with 
1  oz.  of  syrup,  and  \  oz.  powdered  gum,  are  well  mixed  in  a  dry- 
mortar,  stirring  always  in  the  same  direction.  When  it  becomes 
sticky,  a  little  peppermint  or  orange-flower  water  is  added,  and 
4  oz.  distilled  water  gradually  stirred  in.  This  forms  a  most 
elegant  emulsion,  with  scarcely  the  slightest  taste  of  the  oil  ;  it  is 
called  here,  "  Olio  di  Ricini  a  l'lnglese." 
I  fear  that  little  service  will  be  rendered  to  the  Conference  by 
this  very  imperfect  description  of  the  Italian  process  for  obtain- 
ing the  oil,  and  must  apologize  for  my  neglect  in  not  writing 
sooner.  If  at  any  time  I  can  furnish  you  with  any  information 
respecting  the  processes  here  employed  in  the  production  of 
pharmaceutical  products,  I  shall  be  most  happy  to  do  so. 
With  much  respect,  believe  me,  dear  Sir,  yours  truly, 
John  Phillips. 
— London  Pharm.  Jour.  Oct.  1,  1865. 
TEST  FOR  OTTO  OF  ROSES. 
Hager  mixes  five  drops  of  the  otto  to  be  tested  with  twenty 
drops  of  pure  concentrated  sulphuric  acid.  Whether  the  oil  be 
adulterated  or  not,  a  thick  yellowish  brown  or  reddish  brown 
mixture  results.  When  this  mixture  is  cold,  it  is  shaken  up  with 
three  drachms  of  absolute  alcohol.  If  now  the  otto  is  pure,  a 
tolerably  clear  yellowish  brown  solution  results,  which,  after 
heating  to  boiling,  remains  clear.  But  if  the  otto  is  adulterated 
with  geranium,  palm  rose,  or  pelargonium  oil,  the  solution  re- 
mains very  cloudy,  and  in  some  cases  a  darker  fluid  separates,  in 
which  a  deposit  forms.  On  heating  this  solution,  the  sediment 
melts  together,  and  from  the  size  of  the  mass  the  author  infers 
the  degree  of  adulteration.  If,  for  example,  the  mass  has  one- 
fourth  the  volume  of  a  drop,  he  concludes  that  the  otto  was 
mixed  with  at  least  one-third  of  foreign  oil.  If  the  otto  is  adul- 
terated with  spermaceti,  this  substance  separates  and  floats  on 
the  surface  of  the  solution,  or  remains  suspended  in  the  liquid  as 
a  scaly  crystalline  mass.  The  above  test  is  founded  on  the  cir- 
cumstance that  pure  otto  of  rose  forms,  with  strong  sulphuric 
acid,  a  resinous  substance,  which  is  completely  soluble  in  absolute 
