Am  jJu(iy!'i^9arm' }  Gleanings  from  the  German  Journals.  355 
Analytical  Chemistry. — Quantitative  Determination  of  Theobromine 
in  Cacao  and  Chocolate. — G.  Wolfram  recommends  the  following 
method  :  If  shelled  cacao-beans  are  to  be  analyzed  they  are  ground  up  in 
a  hot  mortar  to  a  thick  paste.  10  grams  of  this  mass,  or  20  to  30  grams 
of  chocolate  are  digested  for  some  time  in  hot  water,  treated  with  am- 
moniacal  lead  acetate,  filtered  whilst  hot  and  washed  with  hot  water 
until  the  acidified  filtrate  ceases  to  give  a  precipitate  with  sodium  phos- 
pho-tungstate.  The  filtrate  is  tested  with  caustic  soda,  and  the  liquid 
evaporated  to  50  cc,  acidified  with  sulphuric  acid,  and  the  lead  sulphate 
removed  by  filtration.  The  filtate  is  precipitated  with  a  large  excess  of 
sodium  phospho-tungstate.  The  separation  of  the  slimy  yellowish- 
white  precipitate,  in  flakes,  is  facilitated  by  warming  and  stirring  the 
mixture  gently.  After  several  hours'  standing  the  liquid  is  filtered  and 
washed  with  6  to  8  per  cent,  of  sulphuric  acid.  The  filter  and  the 
precipitate  are  then  treated  in  a  beaker  with  an  excess  of  caustic 
baryta,  the  mixture  warmed,  the  excess  of  barium  hydrate  neutralized, 
by  means  of  sulphuric  acid,  and  any  excess  of  the  latter  thrown  down 
with  barium  carbonate.  The  liquid  containing  the  theobromine  in 
solution  is  filtered  whilst  hot,  and  the  precipitate  washed  with  hot  water. 
The  filtrate  is  evaporated  in  a  platinum  dish,  dried  and  weighed.  Since, 
besides  theobromine,  a  small  quantity  of  baryta  salts  is  always  dissolved 
in  the  liquid,  the  alkaloid  is  removed  by  ignition,  the  residue  moistened 
with  ammonium  carbonate,  evaporated,  heated,  re-weighed  and  the 
■difference  between  the  two  weighings  calculated  as  theobromine. — 
Dingier' s  Poly  tech.  Jour.,  vol.  230,  pp.  240,  241. 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  Louis  von  Cotzhausen,  Ph.G. 
Gelatin  Globules  containing  Potassium  Iodide  are  prepared  suc- 
cessfully by  G.  Berg  by  melting  on  a  water-bath  sufficient  of  the  pre- 
viously prepared  mass,  consisting  of  one  part  gelatin,  one  part  water, 
and  four  parts  glycerin,  adding  the  prescribed  quantity  of  potassium 
iodide,  stirring  until  fully  dissolved,  which  is  the  case  in  a  very  short 
time,  and  pouring  quickly  into  cold  metallic  moulds,  where  the  globules 
solidify  almost  instantly,  while,  if  the  potassium  iodide  is  added  in  the 
beginning,  and  is  heated  with  the  gelatin,  water  and  glycerin  until  the 
