620  The  History  of  Citrine  Ointment.  {^"^Dec'issi!^ 
The  formula  was : 
R    Hydrargyri  pur.,  .  .  .  .    unciam  unani. 
Acidi  nitrosi,  .  .  .         uncias  diias. 
AxLingise  pr^ep.,  ....    libram  unarn. 
Dissolve  the  mercury  in  the  acid,  and  then  mix  the  boiling  liquid 
with  the  lard  previously  melted,  remove  from  the  dish  and  allow  to- 
cool.  The  same  formula  was  used  in  the  Edinburgh  Pharmacopoeia 
of  1792,  but  it  was  ordered  to  be  stirred  diligently  during  the  cooling; 
a  milder  ointment  was  also  official,  containing  half  the  quantity  of  lard. 
In  1803  the  Ediugurgh  Pharmacopseia  ordered  12  ozs.  of  lard  instead 
of  16,  the  milder  ointment  containing  three  times  that  amount.  Not- 
withstanding these  continued  alterations  the  ointment  was  still  very 
unsatisfactory,  it  varied  greatly  with  the  temperature  employed  in^. 
preparing  it,  and  after  keeping  usually  became  gray  with  greenish 
patches,  and  so  hard  that  it  could  sometimes  be  powdered.  This  was 
stated  to  be  due  to  the  oxidation  of  the  lard  by  the  nitric  acid,  and 
many  other  substances  were  tried  as  a  basis,  among  which  the  most 
important  were  butter,  olive  oil,  and  neat's  foot  oil.  Accordingly  we 
find  in  the  Edinburgh  Pharmacopoeias  of  1807,  1809,  1813  and  1817 
a  formula  having  as  a  basis  1  part  lard  to  3  parts  of  olive  oil;  in  that 
of  Dublin,  1807,  1  of  lard  to  4  of  oil;  and  London,  1809,  2  parts  oil 
to  3  of  lard:  still  the  results  were  quite  insatisfactory,  and  many  were 
the  theories  propounded  to  account  for  the  changes  to  which  it  wa& 
liable,  excess  of  nitric  acid,  deficiency  of  nitric  acid,  too  high  or  too  low 
a  temperature,  the  presence  of  salt  in  the  lard,  impure  mercury,  and  a 
fatty  basis  of  unsuitable  nature,  all  received  their  supporters.  Acting^ 
upon  the  first  of  these  theories  the  authorities  of  the  London  Pharma- 
copoeias of  1817,  1824,  1836,  and  1851  ordered  11  drachms  of  acid  in 
place  of  2  ounces,  the  formula  of  the  last  being : 
R    Hydrarg.  pur.,       .  .  .  .  •  ^i, 
Acid,  nitric,     .  .  .  .  .  ^xi, 
Ol.  ollvse,  .....  ^iv, 
Adipis  prsep.,   .  .  .  .  .  ^viii. 
Ft.  unguent. 
They  also  ordered  a  milder  ointment,  containing  one  part  of  strong- 
ointment  to  7  of  lard.  The  Dublin  Pharmacopoeia  of  1850  also  orders 
less  acid,  while  those  of  Edinburgh,  1839  and  1841,  direct  a  larger 
quantity. 
