294 
ON   OLEUM  ARACHIS  RYPOGMM. 
at  620°  it  gives  off  dense  vapors  which  ignite  spontaneously;  if 
the  vessel  is  removed  from  the  fire  and  covered,  the  flame  is 
extinguished;  but  on  removing  the  cover,  contact  with  the  air 
again  ignites  it. 
In  order  to  ascertain  the  applicability  of  this  oil  to  the  pur- 
poses of  the  pharmaceutist,  a  number  of  experiments  were  made 
with  it,  some  of  which  resulted  very  satisfactorily,  and  proved 
that  in  some  respects  it  would  be  a  valuable  addition  to  Pharmacy. 
As  is  generally  known  to  be  the  case,  the  cerate  of  subacetate 
of  lead,  made  according  to  the  U.  S.  P.,  unless  carefully  pro- 
tected from  the  air,  soon  undergoes  a  change,  and  becomes  more 
or  less  rancid.  With  the  view  of  obviating  this  difficulty,  a 
cerate  was  made  according  to  the  officinal  formula  only  substi- 
tuting pea  nut  for  olive  oil ;  the  resulting  cerate  is  of  rather 
softer  consistence,  and  seems  to  keep  better  than  when  made 
with  olive  oil.  A  specimen  on  hand  made  several  months  ago, 
and  exposed  to  the  action  of  the  air,  retains  the  desirable  color 
and  consistence  it  originally  possessed,  and  is  in  every  respect 
quite  as  good  as  when  first  made.  Experiments  were  also  made 
by  substituting  this  oil  for  the  oil  of  sweet  almonds  in  making 
cold  cream,  and  for  lard  in  simple  cerate,  and  resulted  in  the 
production  of  ointments,  equal  in  all  respects  to  those  made  ac- 
cording to  the  officinal  formula.  It  was  observed  that  in  all 
the  preparations  into  which  wax  enters,  the  nut  oil  combined 
more  readily  with  the  wax,  and  was  less  liable  to  become  lumpy 
than  the  oils  generally  used  for  this  purpose. 
The  ointment  of  the  nitrate  of  mercury,  made  from  this  oil 
instead  of  the  neats-foot  oil,  and  made  according  to  the  process 
of  Mr.  Joseph  Laidley  given  in  the  Amer.  Jour,  of  Pharm. 
(xxii.  119,)  yielded  an  ointment  of  a  beautiful  yellow  color, 
and  rather  harder  than  that  made  by  the  officinal  process. 
Another  experiment  was  made  by  replacing  both  the  neats-foot 
oil  and  lard  with  pea-nut  oil ;  the  resulting  ointment  was  of 
rather  a  lighter  orange  color  than  the  other,  and  just  about  soft 
enough  for  use.  Specimens  of  each  of  the  above  ointments 
kept  on  hand  for  some  months  have  undergone  no  change,  either 
in  uniformity  of  color  or  consistence,  and  it  is  thought  that  this 
oil  might  be  substituted  with  propriety  in  the  officinal  process, 
as  it  affords  a  superior  preparation, 
