A%p°rUif;iP894arm-}        Presence  of  Lead  in  Citrates.  173 
In  conclusion,  the  writer  desires  to  correct  an  error  in  the  tabu- 
lated statement  of  the  analysis  published  in  the  February  number, 
in  the  amount  stated  as  inulin,  which  should  be  -71  per  cent,  instead 
of  -35  per  cent. 
THE  PRESENCE  OF  LEAD  IN  CITRATES. 
By  F.  W.  Haussmann. 
The  fact  that  the  citric  acid  of  commerce  is  frequently  found 
mixed  with  particles  of  metallic  lead,  derived  from  the  lead-lined 
tanks  in  which  it  is  crystallized,  is  well  known. 
It  is  generally  accepted  as  true,  that  these  particles  in  no  way  con- 
taminate the  acid  sufficiently  to  produce  deleterious  or  decidedly 
poisonous  effects. 
This  may  be  the  case  while  the  acid  is  in  the  dry  state,  but  a 
different  result  takes  place  if  an  aqueous  solution  is  kept  in  contact 
with  the  lead  particles  for  some  time. 
It  is  an  ancient  observation  that  the  fruit  acids  in  general  have  a 
solvent  action  upon  metallic  lead,  and  this  fact  has  been  taken 
advantage  of  in  the  course  of  a  number  of  crude,  technical  experi- 
ments. 
Citric  acid  also  shares  this  property  and,  although  it  is  doubtful, 
if  its  action  upon  lead  is  of  sufficient  extent  to  produce  a  toxic  dose 
of  a  citrate,  it  must  be  admitted  that  a  certain  amount  is  dissolved, 
sufficient  to  give  decided  results  to  the  application  of  reagents  for 
lead  in  some  soluble  form. 
The  U.  S.  Pharmacopoeia  recognizes  the  possible  presence  of  the 
metal  in  citric  acid,  hence  a  qualitative  method  for  the  determina- 
tion of  this  impurity  is  given  and  the  method  of  application  directed 
would  indicate  that  the  solvent  action  of  the  acid  upon  lead  and 
other  heavy  metals  is  recognized. 
Solubility  of  Lead  in  Citric  Acid. — To  determine  if  citric  acid 
exerted  a  solvent  action  upon  metallic  lead  a  number  of  experi- 
ments were  made. 
A  portion  of  the  acid,  previously  ascertained  to  be  entirely  free 
from  metallic  impurities,  was  dissolved  in  cold  water  and  the  solu- 
tion left  in  contact  with  fine  particles  of  metallic  lead  for  3  hours. 
After  filtration  and  incomplete  neutralization  with  ammonia 
water,  as  directed  by  the  Pharmacopoeia,  the  solution  reacted  imme- 
diately both  to  ammonium  sulphide  and  potassium  chromate. 
