232 
Ointment  of  Mercuric  Nitrate. 
km.  Jour.  Pharm. 
May,  1897. 
CONSIDERATION  OF  SOME  RECENT  SUGGESTIONS 
CONCERNING  OINTMENT  OF  MERCURIC 
NITRATE. 
By  Charts  H.  L,a  Wau. 
The  Pharmaceutical  Journal,  of  February  27,  1897,  page  172, 
contained  an  article  by  P.  W.  Squire,  upon  the  processes  now  offi- 
cial for  the  preparation  of  ointment  of  mercuric  nitrate,  commonly 
called  citrine  ointment. 
Mr.  Squire's  experiments  were  mainly  devoted  to  the  considera- 
tion of  the  differences  now  existing  between  the  quantities  and 
manipulations  directed  by  the  U.S. P.  and  B.P. 
While  he  slightly  favored  the  use  of  a  combination  of  lard  and 
olive  oil  (as  is  authorized  in  the  B.P.)  instead  of  lard  oil  (directed  by 
the  U.S.P.),  Mr.  Squire  acknowledged  the  superiority  of  our  process 
in  previously  acting  on  the  fatty  base  with  a  portion  of  the  nitric 
acid,  instead  of  adding  the  mercury  dissolved  in  the  whole  quantity 
of  nitric  acid,  as  the  B.P.  directs.  His  observations  on  the  varia 
tions  produced  by  the  influence  of  different  temperatures  show  the 
necessity  of  guarding  against  over-heating  the  compound  after  the 
addition  of  the  mercuric  nitrate  solution. 
In  commenting  upon  Mr.  Squire's  paper  in  the  last  number  of 
The  American  Journal  of  Pharmacy  (Vol  69,  p.  209),  Mr.  J.  W. 
England  suggests  some  improvements  on  the  present  officinal  pro- 
cess, which  are  offered  for  trial  and  discussion. 
Mr.  England's  improvements  consist  in  (1)  using  a  proportionate 
amount  of  red  oxide  of  mercury  in  place  of  the  metal ;  (2)  chang- 
ing the  temperature  to  which  the  mixture  should  be  permitted  to 
cool  before  adding  the  mercuric  nitrate  solution ;  (3)  incorporating 
about  5  per  cent,  of  glycerin  with  the  finished  product  when  nearly 
cold. 
The  reasons  given  for  the  substitution  of  red  mercuric  oxide  for 
metallic  mercury  are:  (1)  because  small  quantities  of  the  oxide 
are  more  easily  weighed  ;  and  (2)  because  the  oxide  is  probably 
purer  than  the  commercial  mercury. 
There  are  altogether  six  official  preparations  in  which  metallic 
mercury  is  directed  by  the  U.S. P.,  so  that  a  certain  amount  of 
dexterity  ought  to  be  acquired  in  the  weighing  of  this  elusive  sub- 
stance by  a  pharmacist  who  does  his  own  manufacturing.    As  to 
