A&™£\£!w£'}       Ointment  of  Mercuric  Nitrate.  .525 
OINTMENT  OF  MERCURIC  NITRATE. 
By  Charges  H.  IvaWau,,  Ph.G. 
Unguentum  Hydrargyri  Nitratis,  or  Citrine  Ointment,  as  it  is 
commonly  called,  is  one  of  the  most  difficult  preparations  of  the 
Pharmacopoeia  to  make,  and  at  the  same  time  obtain  uniform 
results.  This  is  not  due  to  lack  of  research  and  experiment,  for 
scarcely  a  preparation  of  the  Pharmacopoeia  confronts  us  with  such 
an  array  of  literature  regarding  its  preparation  and  ingredients,  as 
this  one.  Considering  this  fact,  as  well  as  the  age  of  the  compound, 
which  dates  from  the  seventeenth  century,  it  is  surprising  to  note 
how  many  otherwise  skilful  pharmacists  attain  very  unsatisfactory 
results  in  making  this  ointment. 
It  is  not  the  purpose  of  this  article  to  give  an  historical  account 
of  Citrine  Ointment,  as  that  has  been  ably  done  in  several  previous 
articles.1  However,  it  would  not  be  amiss  to  mention  some  of  the 
fats  suggested  at  various  times  as  a  substitute  for  the  lard  oil  of  the 
present  official  preparation. 
Neatsfoot  Oil,2  Lard,3  Butter,4  Peanut  Oil5,  Almond  Oil6,  Castor 
Oil,6  Palm  Oil,6  Bear's  Oil,7  Ox  Marrow,8  Beef  Suet,9  Stearic  Acid,10 
Petrolatum,11  and  almost  all  of  the  other  fats  from  the  animal  and  the 
vegetable  kingdoms,  and  even  one  from  the  mineral  kingdom,  appear 
to  have  been  experimented  with  in  the  vain  hope  of  finding  some  fat 
or  oil  which  would  make  a  good  and  durable  ointment. 
Several  writers  have  taken  another  course  and  have  tried  to  pre- 
serve the  products  obtained  from  former  processes.  One  advises 
keeping  the  ointment  in  a  jar  and  covering  it  with  a  layer  of  gly- 
cerin to  prevent  oxidation12 ;  others  have  tried  the  addition  of  cam- 
jAm.  Jour.  Phar.,  54,  p.  618  ;  41,  p.  211. 
2Ibid.  1,  p.  171,  3,  p.  85. 
3Ibid.  13,  p.  101. 
4Ibid.  14,  p.  110  :  30,  p.  102  ;  54,  p.  586. 
5 Ibid.  30,  p.  102  ;  45,  p.  460. 
6Ibid.  30,  p.  102. 
7Ibid.  32,  p.  212. 
8 Ibid.  49,  p.  551. 
9Ibid.  51,  p.  438. 
10  Ibid.  51,  p.  438;  58,  p.  8. 
"Ibid.  58,  p.  8. 
1 2Ibid.  52,  p.  300. 
