412 
ON  BED  PRECIPITATE  OINTMENT. 
Dorat,  and  induce  him  to  obtain  still  further  information  respect- 
ing the  manufacture  of  the  so-called  Balsam  of  Peru,  as  well  as 
additional  specimens  of  the  tree.  With  this  view,  I  am  writing 
him  a  few  lines  by  this  mail. 
Believe  me  to  remain,  my  dear  sir, 
Yours,  very  sincerely, 
Danl.  Hanbury. 
ON  KED  PRECIPITATE  OINTMENT, 
By  F.  A.  Keffer. 
To  the  Editor  of  the  American  Journal  of  Pharmacy: 
Sir, — Being  aware  of  the  great  difficulty  in  keeping,  espe- 
cially in  warm  weather,  the  Ung.  Hydrargyri  Oxidi  Bubri,  I 
have  been  lead  to  make  some  experiments  with  the  same,  and 
find  that,  instead  of  using  lard,  if  I  use  Oleum  Bicini,  that  the 
preparation  will  keep  perfectly  well  for  a  great  length  of  time. 
I  have  now  in  my  possession  a  sample  that  has  been  made  over 
two  years,  and  it  is  perfectly  free  from  rancidity,  and  still  retains 
its  original  color,  the  mercury  to  all  appearance  not  having 
become  deoxidized  in  the  least.    My  formula  is 
J$.  Olei  Bicini,  .         .        .  iiiiss. 
Cerse  Albse,  .        .        .  3ss. 
Hydr.  Oxidi  Bubri,  .        .  §ss. 
Melt  the  wax  and  oil  with  a  gentle  heat,  and  when  cool  rub  in 
the  red  precipitate  previously  reduced  to  fine  powder. 
Hoping  the  publication  of  this  will  be  of  some  advantage  to 
Pharmaceutists,  I  remain  yours,  &c, 
Fred.  A.  Keeper. 
Philada.,  July,  1860. 
THE  POISON-OAK  AND  ITS  ANTIDOTE. 
By  Colbert  A.  Canfield,  M.  D. 
In  the  woods  and  thickets  of  California,  as  well  as  on  the 
dry  hill-sides,  and  in  fact  in  every  variety  of  locality,  may  be 
found  a  very  venomous  shrub, — -the  "poison-oak"  or  "poison- 
