Am.  Jour.  Pharm. \ 
November,  1897.  J 
Official  Lead  Preparations. 
567 
of  commerce  is  usually  prepared  from  litharge  more  or  less  impure, 
and  this  may  influence  the  specific  gravity  of  lead  subacetate  solu- 
tion prepared  from  such  salts. 
For  instance,  the  solution  was  made  from  an  acetate  which  the 
writer  prepared  from  a  sample  of  litharge  assaying  96  5  per  cent,  of 
oxide,  the  latter  being  also  employed. 
The  finished  preparation  had  the  specific  gravity  of  1*225,  anc-  re~ 
quired  exactly  25  c.c.  of  normal  sulphuric  acid  for  the  precipitation 
of  13-67  grammes. 
The  specific  gravity  of  lead  subacetate  solution  will  not  answer 
either  for  an  identity  test  or  a  criterion  as  to  percentage 
strength. 
An  aqueous  solution  of  lead  acetate  containing  between  25  and 
28  per  cent,  of  the  salt  will  have  a  specific  gravity  closely  approxi- 
mating 1-195,  the  official  figure  for  Goulard's  extract. 
A  17  per  cent,  solution  of  lead  acetate  was  found  to  have  the 
specific  gravity  of  1-123,  an<^  I3"^7  grammes  required  for  precipita- 
71 
tion  about  14  c.c.  of  —  H2S04. 
An  addition  of  100  grammes  of  lead  oxide  to  1,000  grammes  of 
this  solution,  allowed  to  stand  one  week  with  occasional  agitation, 
yielded  a  filtrate  of  the  specific  gravity  1-207,  which,  however, 
only  required  23  c.c.  —  H2SOd  for  precipitating  the  usual  amount. 
It  will  be  seen  that  although  the  specific  gravity  of  this  solution 
is  in  excess  of  the  pharmacopceial  figure,  it  fell  short  in  the  percent- 
age of  basic  salt,  while  having  a  10  per  cent,  increase  in  water  over 
the  official  amount. 
From  the  above  and  other  results  obtained,  the  writer  draws  the 
conclusion  that  the  specific  gravity  of  liquor  plumbi  subacetatis 
must  be  placed  as  about  1-225,  instead  of  1-195,  tne  pharmacopceial 
figure. 
LIQUOR  PLUMBI  SUBACETATIS  DILUTUS. 
The  official  lead  water  is  one  of  the  preparations  for  which,  due 
to  its  liability  to  chemical  change,  it  is  alike  impossible  to  suggest 
improvement  or  to  fix  a  definite  standard. 
When  recently  prepared,  a  clear  solution  is  obtained.  But  aside 
from  the  procedure  of  many  pharmacists  to  draw  their  distilled  water 
