Am.  Jour.  Pharm  \ 
November,  1897.  / 
Official  Lead  Preparations. 
563 
were  found  to  require  less  than  25  c.c.  for  precipitation  of  13-67 
grammes  of  the  solution. 
Similar  experiments  were  repeatedly  performed,  and  it  was  invari- 
ably found  that  after  a  contact  of  two  hours,  little  or  no  oxide 
passes  into  solution. 
In  one  instance,  the  mixture  of  lead,  salts  and  water  was  allowed 
to  stand  three  weeks  before  filtration,  but  no  difference  was  found 
between  this  and  a  filtrate  of  two  hours'  standing. 
Various  modifications  of  this  process,  such  as  trituration  of  the 
mixed  lead  salts  in  a  mortar  and  subsequently  adding  boiling  dis- 
tilled water,  were  also  tried,  but  furnished  no  improvement  over  the 
method  described. 
OTHER  METHODS  OF  PREPARATION. 
Acetates  of  the  alkaline  earth  metals  also  possess  the  power  of 
dissolving  lead  oxide. 
Of  these,  magnesium  acetate  has  been  suggested  to  prepare  a 
modification  of  Goulard's  extract,  and  particularly  lead  water. 
This  process,  as  given  in  the  Proceedings  of  the  American  Phar- 
maceutical Association  of  1893,  possesses  no  advantage.  It  is 
tedious  and  does  not  furnish  an  official  preparation. 
Of  greater  importance  is  a  process  which  is  based  on  the  fact 
that  if  ammonia  water  is  added  to  a  solution  of  lead  acetate  in  the 
proper  proportion,  a  solution  of  the  basic  salt  is  immediately  pro- 
duced. 
The  following  is  the  process  recommended : 
Seventy-five  parts  of  pure  crystallized  lead  acetate  are  dissolved 
in  165  parts  of  distilled  water  and  1 1  parts  of  water  of  ammonia, 
200  B.,  sp.  gr.  0-923,  are  added. 
In  place  of  the  ammonia  water  of  this  strength,  22  parts  of  the 
official  10  per  cent,  water  can  be  added,  deducting  11  parts  from 
the  amount  of  water  employed  to  dissolve  the  acetate.  The  prep- 
aration is  stated  to  be  immediately  ready  for  use. 
Goulard's  extract,  thus  prepared,  resembles  the  official  prepara- 
tion in  appearance,  has  no  odor  of  ammonia,  but  in  point  of  stability 
possesses  no  advantage,  also  depositing  lead  carbonate  on  prolonged 
standing. 
The  specific  gravity  of  the  solution  was  found  to  be  P208. 
In  the  volumetric  estimation  of  Goulard's  extract,  prepared  by 
