As^ptJember,hi89™'}    Elm  Bark,  Flaxseed  and  Mustard.  463 
seed  meal  it  will  be  followed  by  a  trade  supply  that  will  conform  to 
the  starch  test  of  the  Pharmacopoeia,  but  naturally  at  increased 
price. 
The  pharmacopoeial  test  is,  I  believe,  objectionable  by  reason  of 
the  unnecessary  direction  to  filter  the  infusion,  which,  owing  to  its 
mucilaginous  nature,  is  troublesome  to  say  the  least.  It  may  also 
be  made  more  specific  as  to  details,  and,  owing  to  the  growing  im- 
portance of  this  subject,  nothing  should  be  left  to  conjecture. 
The  test  as  I  apply  it  is  as  follows : 
Boil  I  gramme  of  ground  flaxseed  with  20  c.c.  of  water,  and  cool. 
Mix  0-2  c.c.  test  solution  of  iodine,  U.  S.  P.,  with  10  c.c.  of  10  per 
cent,  sulphuric  acid. 
To  8  c.c.  of  the  flaxseed  mucilage  add  2  c.c.  of  this  iodine  com- 
pound, when,  if  starch  is  present,  a  blue  coloration  will  result.  As 
little  as  0-5  per  cent,  of  starch  is  indicated  by  a  strong  reaction. 
An  admixture  of  but  0-3  per  cent,  of  starch  is  easily  recognizable 
by  this  iodine  test.  Even  the  presence  of  as  little  as  o-i  per  cent, 
of  starch  may  also  be  recognized  by  making  the  mucilage  more 
concentrated,  using  only  10  c.c.  of  water,  instead  of  20  c.c,  to  I 
gramme  of  flaxseed. 
MUSTARD. 
Free  from  starch.— U.  S.  P. 
If  commercial  mustard  seed  be  examined  it  will  be  found,  as  a 
rule,  mixed  with  foreign  seeds.  Among  these  are  to  be  found 
starch-bearing  seeds,  especially  the  seed  of  Chenopodium  (American 
wormseed),  this  being  often  present  and  containing  much  starch. 
If  this  mixed  mustard  be  powdered  and  tested  by  the  usual  iodine 
method  with  small  amounts  of  iodine,  it  will  be  found,  even  in  the 
presence  of  much  starch  paste,  that  the  reaction  will  be  indistinct 
or  evanescent,  if  it  develop  at  all.  This  is  due  to  the  action  of 
iodine  on  volatile  mustard  oil.  In  this  connection  it  may  be 
said  that  when  a  few  drops  of  oil  of  mustard  are  stirred  into  an 
excess  of  iodized  starch  mixture,  the  blue  coloration  will  soon  be 
removed. 
As  a  result  of  a  series  of  experiments  that  were  made  in  order  to 
arrive  at  an  expeditious  method  to  eliminate  the  iodine-absorbing 
power  of  mustard  oil  prior  to  the  testing  for  starch,  the  following 
process  gave  the  greatest  satisfaction : 
