^Jc0tui',i872RM'}  Oleic  Acid  and  some  of  its  Combinations.  461 
at  the  head  of  the  valley  is  ordinarily  as  three  to  four,  sometimes  even 
as  two  to  three. — Pharm.  Journ.,  Lond.,  Sept.  7,  1872. 
OLEIC  ACID  AND  SOME  OF  ITS  COMBINATIONS. 
By  Alfred  W.  Gerrard, 
Dispense?'  and  pharmacist,  Guy's  Hospital. 
The  introduction  of  the  oleates  of  mercury  and  morphia  as  reme- 
dial agents  by  Mr.  J.  Marshall,  F.R.S.,  suggested  to  me  the  follow- 
ing as  capable  of  preparation,  and  as  having  some  therapeutic  value  : 
Mr.  Frank  Clowes,  to  whom  Mr.  Marshall  referred  the  chemical 
question  of  his  paper  ("Lancet,"  May  25th,  1872),  mentions  that  the 
scales  of  peroxide  of  mercury  are  with  difficulty  soluble  in  oleic  acid. 
I  find  this  is  not  so  if  the  peroxide  is  previously  well  levigated.  There 
is  no  necessity,  therefore,  for  preparing  the  fresh  oxide  for  solution 
in  the  oleic  acid. 
The  oleic  acid  used  in  the  following  preparations  is  that  made  at 
the  stearine  candle  factories,  where  it  occurs  as  a  secondary  product. 
It  is  contaminated  with  a  variety  of  impurities,  the  removal  of  which 
is  a  tedious  process.  It  has  the  color  of  olive  oil,  but  a  thinner  con- 
sistence, and  a  slight  tallowy  odor ;  is  soluble  in  all  the  ordinary  fats 
and  oils,  alcohol  and  ether,  but  insoluble  in  glycerin.  It  forms  nor- 
mal and  acid  salts  ;  the  normal  salts  of  the  alkalies  potash  and  soda 
are  the  soluble  soaps  of  the  pharmacopoeia. 
Professor  Miller,  in  his  "Elements  of  Chemistry,"  part  3,  page 
£63-4,  says:  "Pure  oleic  acid,  at  temperatures  above  57°,  forms  a 
colorless  limpid  oil  without  taste  or  smell  ;  it  does  not  redden  litmus 
•even  when  dissolved  in  alcohol ;  at  40°  it  coucretes  into  a  hard  crys- 
talline mass  composed  of  fine  needles.  When  solid  it  undergoes  no 
ohange  in  the  air,  but  when  liquid  it  absorbs  oxygen,  rapidly  acquir- 
ing a  brown  color,  a  rancid  odor,  and  an  acid  reaction  upon  litmus, 
its  point  of  solidification  gradually  becoming  lowered  until  it  falls  be- 
low 0°  Fahrenheit." 
By  reason  of  the  impurities  in  commercial  oleic  acid,  I  find  that  it 
cannot  be  made  to  unite  with  the  salts  used  in  the  following  prepara- 
tions in  equivalent  proportions  ;  it  will,  however,  form  solutions  of  20 
per  cent.,  and  this  I  have  chosen  as  a  suitable  strength  : — 
Oleate  of  Lead  (20  per  cent.) 
Prepared  by  heating  together  oxide  of  lead  one  part,  oleic  acid  four 
