AM6ct°ti87TM-}  of  Nat  Oil  in  Pharmacy,  etc.  461 
Tiaent  still  remains  very  powerful,  the  author  objects  to  the  great  ex- 
cess of  acid.  Suggestions  have  been  made  to  remove  the  excess  of 
acid  by  washing  the  ointment  with  a  large  quantity  of  water;  and 
then  adding  an  equal  weight  of  almond  oil,  but  have  been  rejected  in 
•consequence  of  the  length  and  difficulty  of  the  operation,  and  it  be- 
ing far  from  certain  that  the  whole  of  the  acid  excess  would  be  thus 
removed. 
The  author  having  had  occasion  to  make  a  comparative  investiga- 
tion of  pure  olive  oil  and  the  oil  of  the  ground  nut  (Arachis  hypogoea), 
found  that  the  arachis  oil  possesses  a  great  aptitude  for  the  nitric 
solidification.  Hence  he  conceived  the  idea  of  suppressing  entirelv 
the  lard  in  the  preparation  of  nitrate  of  mercury  ointment.  The 
product  so  obtained  seemed  to  present  such  marked  advantages  as  to 
induce  him  to  make  known  the  process  : 
Mercury,     .  .  .  .  .5  parts. 
Nitric  Acid  (sp.  gr.  1-42),    .  .  .    10  " 
Nut  Oil,     .  .  .  .         .  100  " 
Dissolve  without  heat  the  mercury  in  the  acid ;  pour  the  mercurial 
solution  into  the  oil,  agitating  from  time  to  time  with  a  glass  or  earth- 
enware spatula.  After  two  or  three  hours,  according  to  the  quantity 
operated  upon,  and  at  a  temperature  of  about  20°  C,  the  mixture 
begins  to  take  a  milky  consistence,  which  lasts  for  about  an  hour, 
then  thickens  to  that  of  a  soft  butter.  This  latter  stage  lasts  at  least 
two  hours,  during  any  portion  of  which  time  the  ointment  may  be 
poured  out.  The  mass  spreads  with  perfect  regularity  in  a  paper 
mould ;  the  thickness  of  the  layer  is  uniform,  and  there  is  no  separa  - 
tion between  the  oily  and  mercurial  elements,  showing  that  the  com- 
bination is  complete.  The  product  does  not  set  so  rapidly  as  the  offi- 
cial one;  at  the  end  of  ten  or  twelve  hours  it  is  easily  divided  by  a 
wooden  knife,  but  this  is  more  conveniently  done  after  it  has  stood 
for  twenty-four  hours ;  its  consistence  is  then  similar  to  that  of  cacao 
butter  in  the  summer.  Two  or  three  days  afterwards  it  appears  to 
attain  its  maximum  of  firmness,  and  some  has  been  kept  upwards  of 
two  months  without  showing  any  appreciable  difference  in  its  consist- 
ence. Compared  with  the  Codex  preparation,  the  author  considers 
that  the  ointment  made  with  nut  oil  has  greater  cohesion,  is  not  fria- 
ble, and  appears  much  better  adapted  for  friction,  as  it  melts  and 
spreads  upon  the  skin  with  greater  facility. 
