""'^°'noT''i882^'"'}  Assaying  of  Cinchona.  Alkaloids.  549 
drachm  of  muriatic  acid  ;  when  cool  the  hquid  portion  is  filtered  through 
absorbent  cotton  placed  in  the  neck  of  a  funnel,  into  which  the  powder 
having  been  transferred  is  rather  tightly  pressed,  and  two  fluidounces 
of  water  poured  on  and  allowed  to  percolate.  This  is  added  to  the 
filtrate,  and  the  powdered  cinchona  again  boiled  with  5  fluidounces 
of  water  acidulated  with  30  minims  of  hydrochloric  acid.  This  decoc- 
tion is  filtered  in  the  same  manner  as  the  first,  using  the  same  funnel 
and  cotton.  The  bark  is  then  thoroughly  exhausted  by  percolation 
with  acidulated  water,  the  acid  used  being  muriatic  in  the  proportion 
of  5  minims  to  the  flnidounce.  It  required  about  5  fluidounces  to 
accomplish  this.  All  the  filtrates  are  now  mixed  and  then  refiltered 
through  absorbent  cotton.  The  filtrate  is  next  thoroughly  agitated 
witii  six  fluidrachms  of  chloroform.  When  the  chloroform  has  sub- 
sided the  supernatant  liquid  is  drawn  off  and  the  last  portions  carefully 
•collected  by  means  of  a  pipette.  This  operation  is  repeated  with  six 
more  fluidrachms  of  chloroform.  To  the  acid  decoction  is  added 
solution  of  soda  so  as  to  render  it  strongly  alkaline,  and  to  this  one 
and  a  half  flnidounce  of  chloroform  and  well  shaken.  The  latter 
Jiaving  been  removed  to  a  tared  capsule,  the  decoction  is  again  agitated 
with  six  more  fluidrachms  of  chloroform.  This  having  been  sepa- 
rated is  poured  into  the  capsule  with  the  other  portion  of  chloroform 
and  allowed  to  evaporate  at  a  moderate  temperature.  This  leaves  the 
alkaloids  in  a  comparatively  pure  state,  which  weighed  16'20  grains. 
The  amount  of  alkaloidal  residue  left  by  De  Vrij's  process  after 
•evaporating  the  chloroformic  solution  was  16  grains.  In  order  to  obtain 
the  active  principles  of  the  bark  perfect!)^  pure,  dissolve  this  residue  in 
1  flnidounce  of  water  acidulated  with  hydrochloric  acid,  agitated  with 
2  fluidrachms  of  (chloroform ;  remove  this,  and  having  added  1| 
ounce  of  water  and  the  same  quantity  of  chloroform  to  the  acid  solu- 
tion, render  it  decidedly  alkaline  by  means  of  soda  solution  ;  agitate, 
remove  the  cldoroform  to  a  tared  capsule,  and  rei)eat  the  process  with 
2  more  fluidrachms  of  chloroform,  which,  when  removed,  is  to  be  added 
to  the  rest  and  evaporated. 
By  this  means  a  satisfactory  dttermination  of  the  percentage  of  active 
j)rinciples  of  Peruvian  bark  can  bo  obtained  without  much  trouble.  The 
freshly  i)recipitated  alkaloids  are  soluble  in  chloroform,  which  affords 
a  convenient  mode  of  se])arating  them.  The  various  st(^j)s  of  this  assay 
will  be  readily  understood.  ]3y  boiling  the  bark  in  acidulated  water 
the  natural  combinations  of  the  alkaloids  are  br()k(^n  up  by  means  of 
die  stronger  acid.   Agitation  witli  chloroform  in  the  first  j)]ace,  before 
