490  Potassio-Bismuthous  Iodide  as  a  Test  {^'°ocT'i882''™' 
German  linseed  oil.  Saponified  olei'n  and  twice  purified  cotton-seed 
oil  are  used  in  some  cases. 
Seidemann  (^^  Seifenfabrikant/'  1881,  153)  describes  the  preparation 
of  transparent  glycerol  soft  soap.  The  oils  used  for  the  manufacture 
of  this  soap  must  be  bleached.  In  other  respects  the  preparation 
resembles  that  of  other  soft  soaps.  The  bleaching  is  effected  in  the 
following  manner :  The  oil  is  heated  with  direct  steam  and  mixed 
Avith  5  to  8  per  cent,  of  potash-ley  of  28 °B.  It  is  agitated  thoroughly, 
then  allowed  to  remain  quiescent.  The  precipitate  which  subsides  is 
used  for  the  manufacture  of  darker-colored  soaps. 
In  order  to  prevent  the  freezing  of  transparent  soap  it  is  recom- 
mended to  use  linseed  oil  in  its  preparation.  For  washing  woolen 
goods,  Menzies  ("  Seifenfabrikant,''  1881,  169)  recommends  the  use  of 
neutral  potash  soap,  which  is  said  to  supersede  soda  soaps. — Jour. 
Chem..  Soc  ,  Aug.,  1882 ;  from  Dingl.  polyt.  J".,  vol.  244. 
POTASSIO-BISMUTHOUS  IODIDE  AS  A  TEST  FOR 
ALKALOIDS. 
By  F.  Mangini. 
DragendorfF,  in  his  Manual  of  Toxicology,  recommends  this  com- 
pound as  one  of  the  most  delicate  tests  for  alkaloids,  but  adds  that  it 
cannot  be  employed  to  distinguish  one  alkaloid  from  another,  as  it 
gives  orange-colored  precipitates  with  most  of  them.  The  author  of 
the  present  paper,  however,  finds  that  the  characters  of  this  reagent 
vary  considerably  according  to  the  manner  in  which  it  is  prepared. 
When  obtained  by  the  process  described  by  DragendorfP,^  it  produces 
a  turbidity  even  in  pure  water ;  but  when  prepared  by  mixing  3  parts 
potassium  iodide  with  16  parts  liquid  bismuth  iodide  and  3  parts 
hydrochloric  acid,  it  does  not  give  any  turbidity  with  water,  and  is  an 
extremely  delicate  test  for  alkaloids,  serving  also  to  distinguish  many 
of  them  one  from  the  other  by  the  various  gradations  of  color  of  the 
precipitates  and  their  alterations  after  long  standing. 
The  following  are  the  results  obtained : 
1  DragendorfF' s  directions  are  ("  Phar.  Zeits.  f.  Russland,"  v.,  p.  82) :  Dis- 
solve bismuth  iodide  in  warm  concentrated  aqueous  solution  of  potassium 
iodide  and  add  of  the  latter  solution  a  bulk  equal  to  that  required  for  dis- 
solving the  bismuth  iodide.  Editor  Am.  Jouk.  Phar. 
