AmMa^i9oiarnJ'}    Contributions  from  H.  M.  Gordin.  213 
to  obtain  from  several  other  methods.  Possibly  by  further  trials 
another  method  might  be  found,  the  results  of  which  will  approach 
those  obtained  by  the  standard  method  better  than  those  obtained 
by  method  B. 
CINCHONA  BARK. 
After  several  trials  the  method  given  below  was  found  to  give 
good  results.  As  in  the  case  of  nux  vomica,  an  acid  menstruum 
had  to  be  resorted  to,  no  neutral  menstruum  with  or  without  gly- 
cerine giving  complete  exhaustion.  As  acetic  acid  did  not  improve 
much  the  exhaustion,  diluted  hydrochloric  acid  was  taken.  The 
assay  was  made  with  a  view  of  estimating  the  total  alkaloids  as  well 
as  the  ether  soluble  alkaloids.  As  alkalimetric  factor  of  ether  solu- 
ble alkaloids,  the  mean  diacid  factor  of  quinine  and  cinchonidine 
N 
was  taken,  which  for  acid  is  0-003 85. 1 
40 
THE  STANDARD  METHOD. 
Ten  grammes  of  cinchona  bark  in  No.  60  powder  were  moistened 
with  5  c.c.  of  a  mixture  containing  50  per  cent,  alcohol  and  2  per 
cent,  hydrochloric  acid,  and  the  extraction  finished  in  the  same  way 
as  that  of  nux  vomica,  using  hydrochloric  acid  instead  of  phosphoric. 
After  concentration  in  vacuo,  the  liquid  was  made  up  to  100  c.c,  fil- 
tered, and  25  c.c.  of  the  filtrate  (2-5  grammes  drug),  after  making 
strongly  alkaline  with  sodium  hydrate,  were  shaken  out  three  times 
with  a  mixture  of  three  parts  ether  and  one  part  chloroform,  using 
30  ex.  each  time.  The  ether-chloroform  was  shaken  up  with  a  lit- 
tle calcined  magnesia,  filtered  into  a  tared  flask,  the  vessel  and  filter 
well  washed  with  ether-chloroform,  and  the  liquid  completely 
removed  by  distillation.  After  drying  the  flask  at  1300  C.  for  one 
hour,  it  was  cooled  in  desiccator  and  weighed.  This  gave  the  total 
alkaloids  in  2-5  grammes  of  drug. 
To  the  flask  containing  the  total  alkaloids,  10  c.c.  absolute  ether 
and  a  few  grammes  coarse  clean  quartz  was  added  and  the  flask 
shaken  in  a  horizontal  plane  till  all  the  adhering  matter  was  rubbed 
off  by  the  quartz  from  the  walls;  the  liquid  was  then  filtered  through 
a  small  dry  filter  into  another  flask,  the  first  flask,  the  quartz  and 
the  filter  washed  three  times  with  absolute  ether,  using  5  c.c.  each 
As  will  be  shown  in  a  subsequent  paper. 
