Am.  Jour.  Pharm.  > 
May,  1913.  / 
Lead  Number  of  Asafetida. 
ON   THE   METHOD   FOR   DETERMINING   THE  LEAD 
NUMBER  OF  ASAFETIDA. 
By  J.  R.  Rippetoe,  P.D. 
The  "  lead  number "  standard 1  for  asafetida  and  its  applica- 
tion as  a  test,  for  freedom  from,  or  limit  of  foreign  gum  resins, 
in  passing  this  drug  at  the  ports  of  entry,  New  York  in  particular, 
has  been  criticised  by  several  well  known  chemists  (see  below) 
but  the  method  for  determining  the  "lead  number"  does  not  seem 
to  have  been  as  closely  studied. 
In  the  spring  of  19 12  I  had  an  occasion  to  consider  this  method, 
the  particulars  having  been  given  to  me  by  Dr.  Seil  of  the  Bureau 
of  Chemistry,  who  stated  at  that  time  that  asafetida  had  a  "  lead 
number"  of  215  by  the  method  given  below,  and  that  they  were 
inclined  to  reject  all  importations  with  a  number  below  190.  The 
recently  published  figure  for  asafetida  is  222.1 
In  making  some  preliminary  experiments  upon  selected  tears 
of  asafetida  I  found  the  values  to  vary  as  much  as  66  upon  the  same 
sample.  These  results  were  called  to  the  attention  of  the  Govern- 
ment Chemists  who  expressed  considerable  surprise  since  they  had, 
up  to  that  time,  never  found  the  results  to  vary  to  any  appreciable 
extent. 
A  recent  abstract 2  states  that  the  "  method  has  been  proposed  as 
being  the  most  accurate  test  showing  both  the  quality  of  the  gum 
and  possible  adulterants." 
Five  samples  were  examined  by  E.  J.  Parry  3  who  found  the 
"lead  number"  to  vary  from  144  to  172,  and  he  expressed  the 
belief  that  there  is  no  authority  for  assuming  that  220  or  there- 
abouts represents  even  the  approximate  value  of  genuine  asafetida. 
Harrison  and  Self  4  examined  21  samples  and  found  the  values 
to  vary  from  18  to  250,  and  on  repeating  the  determination  in  several 
cases  they  found  a  variation  of  50  where  a  half  strength  lead  solu- 
tion was  used. 
The  following  results  are  given  in  support  of  my  claim  that  the 
1Merril  and  Seil,  1912  Annual  Convention  of  the  Association  of  Official 
Agricultural  Chemists. 
2  American  Druggist,  Jan.,  1913.  17. 
3  Chem.  and  Drug.,  1913,  V.  93,  p.  180. 
4  Pharm.  Journal,  Feb.  15,  1913,  p.  218. 
