Am.  Jour.  Pharm.) 
July,  1910.  \ 
Analysis  of  Ointments. 
323 
the  sulphuric  acid  does  not  turn  dark  on  boiling.  Since  the  compara- 
tively large  amount  of  free  sulphuric  acid  present  may  be  objection- 
able during  the  final  procedure,  it  can  be  driven  off  for  the  most  part 
over  a  Bunsen  burner  without  loss  of  metal.  The  last  traces  of  the 
oxides  of  nitrogen  are  removed  by  diluting  the  residue  with  water 
and  heating  to  the  boiling  point  for  a  short  time.  The  further 
treatment  of  the  residue,  now  free  from  organic  matter,  is  dependent 
on  its  chemical  composition. 
Alkaloids  and  Narcotic  Extracts. — A  sufficient  amount  of  the 
ointment,  containing  about  0.03  of  the  alkaloid,  is  subjected  to 
Stas-Otto's  method  and  the  alkaloid  so  separated  either  weighed 
or  titrated  with  standard  acid  using  cochineal  as  indicator.  The 
quantity  of  the  alkaloid  found,  if  due  to  a  narcotic  extract,  will 
usually  give  an  idea  of  the  amount  of  the  latter. 
Mineral  Oil,  Paraffin,  Vaselin,  Ceresin. — In  admixtures  with 
saponifiable  fat,  oil,  etc.  One  to  two  grammes  of  the  material 
are  saponified  on  the  water  bath  with  an  excess  of  a  4  per  cent, 
alcoholic  solution  of  potassium  hydroxide.  For  details  (see  qual. 
analysis  under  mineral  oil).  Any  volatilized  alcohol  should  be  re- 
placed to  keep  volume  constant.  After  saponification  the  alcohol 
is  driven  off  for  the  most  part,  the  mixture  transferred  to  a  separat- 
ing funnel,  made  up  with  water  to  about  80  c.c.  and  thoroughly 
shaken  with  50  c.c.  of  ether.  The  latter  will  dissolve  the  hydros- 
carbon,  the  aqueous  layer  retaining  the  soap.  If  the  separation 
of  the  ethereal  solution  does  not  occur  readily,  a  few  c.c.  of  alcohol 
may  be  added  to  break  up  any  emulsion  by  giving  the  liquid  a  slight 
rotary  movement.  The  aqueous  solution  is  removed  and  the  ether 
in  separator  agitated  with  10  c.c.  of  water  to  which  a  few  drops 
of  caustic  alkali  have  been  added.  This  is  run  off,  the  ether  shaken 
with  water,  the  latter  removed  and  the  ethereal  solution  collected 
in  a  tared  flask.  The  aqueous  liquid  is  twice  treated  in  separator 
with  fresh  ether  as  before,  each  time  washing  the  ether  and  adding 
it  to  the  first  portion.  After  reclaiming  the  ether  by  distillation,  the 
flask  containing  the  hydrocarbon  is  heated  at  ioo°  C.  for  one  hour 
and  weighed.  Beeswax  and  spermaceti  yield  on  saponification 
myricyl  and  cetyl  alcohol,  respectively,  which  bodies  are  soluble 
more  or  less  in  ether.  Cetyl  alcohol  can  be  separated  from  the 
hydrocarbon  by  treating  the  ether  residue  with  strong  alcohol,  which 
will  dissolve  it.  leaving  the  hydrocarbon  behind.7 
Substances  Soluble  in  Alcohol. — Proceed  as  stated  under  quali- 
