562 
Official  Lead  Preparations. 
(  Am.  Jour.  Pharm. 
\  November,  1897. 
A  few  turns  of  the  vessel  will  dissolve  the  salt. 
100  grammes  of  lead  oxide,  previously  sifted,  are  now  added  in 
divided  portions,  thoroughly  shaking  the  bottle  after  each  addition. 
In  from  five  to  ten  minutes,  on  repeated  thorough  agitation,  the 
yellow  color  of  the  oxide  will  have  changed  to  white. 
The  mixture  is  allowed  to  stand  two  hours  or  until  cold,  with  oc- 
casional agitation,  and  filtered,  with  observation  of  the  usual  precau- 
tions. 
The  solution  thus  prepared  will  fulfil  the  requirements  of  the 
Pharmacopoeia  in  all  particulars. 
The  only  precautions  necessary  are  the  observation  of  the  liability 
of  fracture  of  the  bottle,  unless  the  same  is  previously  warmed,  and 
the  protection  of  the  hands  with  gloves  or  a  towel  to  prevent 
burning. 
The  oxide  must  be  added  in  divided  portions,  as  the  full  addition 
is  liable  to  be  followed  by  caking,  with  consequent  less  rapid 
solution. 
The  question  may  be  raised — will  this  comparatively  brief  contact 
of  the  lead  salts  suffice  to  complete  the  solution,  or,  by  further 
prolonged  maceration,  will  more  of  the  oxide  be  not  taken  up  ? 
To  determine  this  point,  the  following  trial  was  made :  The  pro- 
cess described  was  employed,  preparing  1,000  grammes  of  the 
solution. 
After  a  contact  of  exactly  two  hours  100  c.c.  of  the  solution  were 
filtered  off  and  marked  filtrate  No.  I. 
The  remainder  of  the  solution  was  allowed  to  stand  twenty-four 
hours  longer,  with  occasional  agitation. 
An  additional  ioo  c.c.  were  again  filtered  and  marked  No.  2. 
The  remaining  portion  was  allowed  to  stand  forty  eight  hours 
more,  and  a  third  portion  of  IOO  c.c,  marked  No.  3,  filtered  off. 
■    The  final  remaining  mixture  was  allowed  to  stand  eight  days,  with 
occasional  agitation,  making  the  total  time  of  maceration  from  the 
time  of  preparation  about  twelve  days,  and  filtered. 
The  solutions  were  each  examined  in  turn  as  to  specific  gravity 
and  percentage  of  basic  salt,  according  to  pharmacopceial  direc- 
tions. 
The  respective  specific  gravities  were  all  found  to  be  identical,  and 
the  estimation  with  normal  sulphuric  acid  gave  little  variation,  in  no 
case  being  more  than  a  fraction  of  a  cubic  centimetre,  and  none 
