348  Determination  of  Lupulin  in  Hops.  {Xm-j*™;m™nx- 
DETERMINATION  OF  LUPULIN  IN  HOPS.1 
By  F.  Reinitzer. 
A  portion  of  the  hops  (not  weighed)  is  sifted  by  Haberlandt's 
process,  and  any  grains  which  pass  through  the  sieve  removed  with 
forceps.  The  lupulin  is  then  weighed,  shaken,  and  washed  with 
chloroform  into  a  dry  filter,  in  which  it  is  then  wrapped  and 
extracted  with  chloroform  for  about  an  hour.  When  dry,  it  is 
removed  from  the  filter-paper  to  the  weighing  glass  previously  used, 
and  weighed.  The  amount  of  lupulin  husks  is  thus  determined,  and 
that  of  the  lupulin  found  by  subtracting  this  amount  from  the 
original  weight. 
A  second  weighed  portion  of  the  hops  is  then  extracted  with 
chloroform  in  a  Soxhlet's  apparatus,  shaken  on  a  sieve,  the  pieces 
of  leaf  removed  with  forceps,  and  the  lupulin  brushed  through.  The 
sifted  portion  is  again  sifted  to  obtain  it  free  from  grains.  The  pure 
lupulin  husks  are  now  weighed,  and  from  the  numbers,  with  the 
help  of  those  previously  obtained,  the  original  weight  of  lupulin  is 
calculated.  The  method  gives  much  more  concordant  results  than 
that  originally  employed  by.  Haberlandt,  and  gives  a  better  insight 
into  the  composition  of  hops  than  was  previously  possible.  Examples 
of  analyses  are  given  which  support  this  statement. 
CAFFEINE  TRI-IODIDE. 
By  P.  W.  Squire. 
As  paragraphs  relating  to  this  compound  have  appeared  in  the 
"Commentary"  of  The  Chemist  and  Druggist,  February  15  and 
May  3,  and  as  some  uncertainty  seems  to  exist  regarding  the  con- 
stitution of  the  body  prescribed  under  this  name,  the  following  notes 
may  be  of  interest. 
For  the  confusion  of  formulae  which  has  arisen  in  connection  with 
the  subject,  the  original  paper  by  Professor  Tilden  (Jour.  Chem.  Soc., 
1865,  page  99)  is  primarily  responsible.  After  reading  that  "the 
results  of  experiments  undoubtedly  point  to  the  formula  2(C8H1QN4- 
O.J3)3H20,"  one  does  not  naturally  expect  to  find  the  author,  after 
further  experiment,  altering  the  formula  on  the  succeeding  page  to 
2(C8H10N4O2.HI.I2)3H2O,  a  change  which  gives  a  totally  different 
idea  of  its  constitution  and  method  of  preparation.    Misled  by  the 
1  Bied.  Centr.,  xviii,  859.   Reprinted  from  Jour.  Chem.  Soc.t  April,  p.  431. 
