Am.  Jour.  Pharm.  ( 
July,  1910.  f 
Analysis  of  Ointments. 
315 
in  the  first  case  is  generally  the  easier  one.  Notwithstanding  the 
difficulty  encountered  in  detecting  fat,  oil,  wax,  etc.,  in  a  mixture 
and  the  frequent  impossibility  of  their  estimation,  the  analyst  pos- 
sessing sufficient  pharmacognostic  knowledge  may  be  able  to  combine 
the  analytical  data  found  with  his  knowledge  of  the  materia  medica 
to  obtain  a  satisfactory  result  in  duplicating  the  original,  if  this  was 
the  purpose  in  view.  A  correct  qualitative  and  approximately 
quantitative  determination  of  the  principal  constituents,  medicinal 
or  cosmetic,  which  do  not  belong  to  the  excipient,  viz.,  alkaloids, 
salts,  sulphur,  glycerin,  etc.,  can  be  expected  however  from  the 
analysis.  The  consistence  of  the  excipient,  if  it  should  prove  to  be 
a  mixture  the  constituents  of  which  have  been  found,  can  be  repro- 
duced if  necessary  by  experiment  when  the  iodine  number,  saponifi- 
cation number,  melting  point,  specific  gravity,  etc.,  do  not  give  any 
clue  concerning  the  proportions. 
Details  in  reference  to  the  ointment  to  be  analyzed,  stating  its  use 
and  effect,  antiseptic,-  anaesthetic,  for  inflammatory  conditions,  etc., 
or  if  for  cosmetic  purpose,  bleaching  and  whitening  the  complexion, 
massage,  liver  spots,  etc.,  often  give  valuable  information  about  the 
ingredients  which  might  be  expected  as,  for  example,  mercury  bichlo- 
ride, certain  alkaloids,  hydrogen  peroxide,  salicylic  acid,  camphor, 
etc.  With  this  preliminary  knowledge  one  is  often  able  to  readily 
detect  the  one  or  the  other  constituent.  A  careful  study  of  any 
literature  accompanying  the  ointment  is  also  advised. 
A  systematic  arrangement  how  to  proceed  with  the  analysis  which 
can  be  used  for  all  cases  naturally  can  not  be  given  and  must  be 
worked  out  after  making  some  preliminary  and  qualitative  tests. 
The  following  procedure  is  suggested : 
1.  Physical  examination:  color,  odor,  consistence,  taste. 
2.  Microscopic  examination. 
3.  Preliminary  tests. 
4.  Analysis,  qualitative  and  quantitative. 
5.  If  indicated,  preparation  of  a  duplicate  and  comparison  with 
the  original. 
In  order  to>  ascertain  if  an  ointment  is  easily  absorbed  by  the  skin, 
its  melting  properties  and  stickiness,  a  little  of  the  ointment  may  be 
rubbed  in  on  the  back  of  the  hand,  at  the  same  time  certain  odors 
might  be  noticeable  as,  for  example,  the  odor  of  cacao  butter. 
Microscopic  Examination. — Spread  a  small  amount  of  the 
ointment,  about  the  size  of  a  match's  head,  on  a  slide,  using  the 
