PURIFICATION  OF  DEXTRIN. 
327 
copper  compounds  may  be  readily  obtained  from  it  in  large 
quantities. —  Wittstein  s  Viertelj.  Schr.,  1870,  281 — 286, /rom 
Ber.  der  deutschen  Chem.  Gesellsch.,  1868,  Nos.  7  and  8. 
J.  M.  M. 
PURIFICATION  OF  DEXTRIN. 
By  Dr.  H.  Hager. 
R.  Forster  has  analyzed  some  commercial  dextrin  with  the 
following  results  : 
Dextrin,  7245    70-43    63-60    59-71    49-78  5-34 
Sugar,  8-77     1-92     7-67     5-76     1-42  0-24 
Insoluble  matter,  13-14  19-97  14-50  20-64  30-80  86  47 
Water,  5-64     7-68    14-23    13-89    18-00     7  95 
.The  insoluble  matter  consists  mainly  of  unaltered  starch. 
Dextrin  is  a  very  good  vehicle  for  dry  narcotic  extracts  ;  it 
has  also  been  recommended  by  Becker  for  internal  use  as  an 
excellent  stomachic  ;  for  medicinal  use,  therefore,  dextrin  must 
be  purified,  which,  according  to  Ilager,  is  best  accomplished  in 
the  following  manner : 
10  parts  dextrin  are  dissolved  in  a  cylindrical  vessel  in  18 
parts  cold  distilled  water  by  agitation  ;  after  standing,  the  clear 
solution  is  decanted  or  strained  through  flannel  and  mixed  with 
IJ  to  2  volumes  of  95  per  cent,  alcohol.  The  liquid  is  decanted 
from  the  doughy  precipitate  which  is  dissolved  in  little  distilled 
water,  and  the  solution  spread  upon  glass  or  porcelain  plates  to 
dry  in  a  warm  place. 
Purified  in  this  Avay  and  rubbed  to  powder,  dextrin  is  a  whitish 
or  white  powder,  which  dissolves  in  distilled  water  to  a  clear, 
yellowish,  nearly  inodorous  solution,  of  a  mild  and  sweetish 
mucilaginous  taste  ;  diluted  with  water  it  must  acquire  merely  a 
faint  violet  tinge  with  iodine  water,  owing  to  the  presence  of  a 
small  quantity  of  soluble  starch,  which  is  of  no  importance.  To 
free  the  dextrin  entirely  from  this  starch,  the  clear,  aqueous 
solution  is  mixed  with  enough  alcohol  to  produce  a  strong  tur- 
bidity, decanted  after  standing  for  a  week  and  then  completely 
precipitated ;  or  the  impure  solution  of  10  dextrin  in  18  water  is 
mixed  with  3  parts  of  alcohol,  decanted  after  a  week  and  then 
precipitated  by  IJ  volumes  of  alcohol. —  Wittsteins  V.  Schr., 
1870,  113-115.  J.  M.  M. 
