(3)  viii,  99-

Kola  Nuts — Comparative  Assay  of  the  African  and  Jamaica  Sorts, —
Alfred  R.  L.  Dohme  and  Hermann  Engelhardt  have  made  comparative
assays  of  African  and  Jamaica  kola  nuts,  employing  two  methods :  the  one
similar  to  that  of  Schlotterbeck  and  Knox  (see  Proceedings  1895,  334-
338),  which  consists  in  the  extraction  of  the  drug  with  chloroform;  the
other,  a  method  of  their  own,  which  depends  upon  the  extraction  of  the


6oO  REPORT   ON   -fiHE   PROGRESS  OF   PHARAtACY.
nuts  with  33J/S  per  cent,  alcohol,  and  is  carried  out  as  follows :  The  pow-
dered nuts  are  boiled  in  an  Erlenraeyer  flask  with  an  inverted  condenser  or
long  tube  attached,  on  a  water-bath  for  three  hours,  with  a  mixture  of  two
parts  of  water  and  one  part  of  alcohol  by  volume.  Part  of  the  starch  will,
of  course,  be  hydrolized,  but  not  sufficient  to  render  filtration  impossible.
After  cooling,  the  contents  of  the  flask  are  filtered,  the  filtrate  evaporated
nearly  to  dryness  in  a  porcelain  dish  on  a  water  bath,  the  still  moist  resi-
due is  mixed  with  calcined  magnesia  and  sand,  and  evaporated  to  com-
plete dryness,  stirring  carefully  and  frequently.  The  dry  powder  is  then
boiled  with  chloroform  for  half  an  hour  in  an  Erlenmeyer  flask,  provided
with  a  reversed  condenser,  on  a  water  bath  ;  the  contents  of  the  flask  are
allowed  to  cool,  and  are  then  filtered  into  a  tared  flask.  The  chloroform
is  distilled  off*,  the  flask  is  heated  on  a  water-bath  at  loo**  C,  and  weighed,
and  the  excess  of  weight  over  the  tare  of  the  flask  taken  as  the  weight  of
the  caffeine  in  the  sample.
