296 
Lead  in  Tartrates. 
Am.  Jour.  Pharm. 
June,  1894. 
This  statement  is  based  on  the  fact  that  in  the  writer's  expe- 
rience the  reactions  obtained  for  lead  in  tartrates  were  considerably- 
less  prominent  than  in  the  case  of  citrates. 
Those  of  greatest  importance  to  the  pharmacist  and  most  de- 
manded by  the  public  are  potassium  bitartrate  or  cream  of  tartar, 
potassium  and  sodium  tartrate  or  Rochelle  salt,  and  the  neutral  tar. 
trate  of  potassium. 
POTASSIUM  BITARTRATE. 
The  cream  of  tartar  of  commerce  does  not  appear  to  be  perfectly 
free  from  metallic  impurities,  which  is  probably  due  to  its  method 
of  preparation. 
Several  samples,  on  being  subjected  to  the  pharmacopceial  tests, 
revealed  the  presence  of  traces  of  lead. 
This  is,  however,  not  to  the  same  extent  as  found  in  the  case  of 
commercial  citrates. 
Other  samples  again,  when  subjected  to  an  examination,  gave 
perfectly  negative  results  as  to  any  metallic  presence. 
ROCHELLE  SALT. 
Some  ten  samples  of  this  salt  were  subjected  to  the  various  tests 
for  lead,  none  of  which  gave  any  indication  whatever  of  its 
presence. 
The  Rochelle  salt  of  commerce  appears  to  possess  a  high  degree 
of  purity,  in  the  crystalline  as  well  as  the  powdered  state. 
In  connection  with  this  it  may  be  stated  that  the  contents  of  a 
number  of  Seidlitz  powders  were  also  examined. 
While  the  contents  of  the  white  acid  papers  occasionally  showed 
small  particles  of  metallic  lead,  in  a  few  cases  also  giving  indication 
of  its  presence  in  solution,  those  of  the  blue  Rochelle  salt  papers 
were  found  to  be  free  from  the  same. 
A  similar  statement  can  also  be  made  regarding  the  Seidlitz  mix- 
ture of  commerce,  which,  while  occasionally  varying  in  composition, 
is  free  from  any  metallic  presence. 
To  determine  whether  tartrates  exerted  any  action  upon  metallic 
lead,  a  number  of  particles  of  the  metal  were  allowed  to  remain  in 
contact  with  a  25  per  cent,  solution  of  Rochelle  salt.  This  solution 
was  found  to  be  perfectly  neutral  as  well  as  free  from  lead. 
After  a  contact  of  six  hours,  the  solution  was  examined  and 
