nel^'i882 }     Estimation  of  Total  Alkaloids  in  Bark.  291 
The  following  is  the  method  as  modified  by  the  author:  10  grams 
of  finely-powdered  bark  are  introduced  into  a  well-closed  bottle  and, 
lifter  being  carefully  tared,  200  grams  of  the  ethereal  liquid  are  added. 
The  whole  is  now  shaken  at  intervals  during  an  hour,  this  length  of 
time  having  been  ascertained  by  comparative  experiments  to  be  suffi- 
cient. The  bottle  is  then  again  weighed  and,  if  evaporation  have 
taken  place,  the  necessary  quantity  of  ether  mixture  is  added. 
As  much  as  possible  of  the  clear  liquid  is  now  poured  off  into  a 
ilask,  and  the  bottle  again  weighed ;  the  difference  in  weight  gives  the 
amount  of  solution  taken.  The  ether  is  then  recovered  by  distillation, 
and  the  residual  liquid,  containing  alkaloid  and  waxy  matter,  is  trans- 
ferred to  a  tared  porcelain  dish  and  glass  rod,  the  flask  being  washed 
with  a  little  spirit.  The  evaporation  is  now  continued  on  the  water- 
bath  until  the  weight  is  constant.  This  gives  the  amount  of  crude 
alkaloid.  For  instance,  10  grams  of  succirubra  bark  were  digested 
with  200  grams  of  ethereal  liquid.  159*8  grams  of  the  clear  solution 
gave  a  residue  of  U'78  gram,  or  9*76  per  cent,  of  crude  alkaloid. 
To  estimate  the  pure  alkaloids,  the  crude  residue  is  dissolved  in 
dilute  hydrochloric  acid,  filtered,  washed  as  long  as  the  washings  pre- 
cipitate with  solution  of  soda,  and  the  whole  made  alkaline  and  shaken 
with  chloroform.  After  standing  twelve  hours,  the  clear  chloroformic 
solution  is  run  into  a  flask  and  evaporated  by  distillation.  The  residue 
is  transferred,  with  a  little  spirit,  to  a  tared  dish  and  stirrer,  and 
heated  on  the  water-bath  till  the  weight  is  constant.  Particular  atten- 
tion should  be  paid  to  the  latter  point.  In  the  instance  referred  to, 
0*648  gram  of  alkaloid  was  obtained,  equivalent  to  8*11  per  cent.,  or 
about  1 J  per  cent,  less  than  the  amount  of  crude  alkaloid.  The  author 
is  of  opinion  that  by  estimating  the  crude  alkaloid  and  deducting  IJ 
per  cent.,  a  result  will  be  arrived  at  with  loss  of  but  little  time,  which, 
for  the  practical  purposes  of  the  pharmacist,  will  be  sufficiently  near 
the  truth.  Of  course  the  same  method  is  applicable  for  the  examina- 
tion of  the  ext.  cinch,  liq.  (De  Vrij). 
From  a  sample  of  cinchona  bark,  10*01  per  cent,  of  pure  alkaloid 
-was  obtained,  whilst  a  former  estimation,  by  the  lime  and  spirit 
method,  had  yielded  10*02  per  cent.  The  close  agreement  of  these 
two  determinations  confirms  the  reliability  of  this  method,  which  the 
-author  confidently  recommends. — Phar,  Jour,  and  Trans.,  March  12, 
3882. 
