"28 
New  Quinimetric  Process. 
f  Am.  Jour.  Pharm. 
\     Jan.  1,  1873. 
"weighing,  all  the  quinia  contained  in  the  cinchona  barks  (the  decoc- 
tion method  extracts  coloring  matter  and  changes  the  active  princi- 
ples, while  the  lixiviation  process  yields  very  weak  liquors,  in  which 
a  portion  of  the  alkaloids  are  kept  in  solution),  I  have  devised  a  method 
which  may  be  carried  out  as  follows  : — A  good  average  sample  of  the 
bark  is  ground  to  powder,  and  passed  through  a  fine  horse-hair  sieve ; 
20  grms.  of  this  powder  are  intimately  mixed  with  from  6  to  8  grms. 
of  slaked  lime,  mixed  with  35  grms.  of  water,  and  the  mixture  of 
quina  bark  and  pasty  lime  dried  at  a  gentle  heat ;  the  cake  thus 
formed  is  reduced  to  a  coarse  powder  and  pressed  into  a  conically- 
shaped  glass  tube  (or  a  funnel  with  stop-cock  and  glass  stopper) ; 
chloroform  is  then  gradually  poured  on  to  the  contents,  care  being 
taken  to  cork  the  tube  at  the  top  ;  150  grms.  of  chloroform  will  be  a 
sufficient  quantity,  but  it  is  best  to  ascertain  if  the  bark  is  exhausted 
by  evaporating  a  few  drops  of  the  last  portion  of  the  chloroform  in  a 
porcelain  basin  ;  the  residue  should  be  treated  first  with  dilute  sul- 
phuric acid,  and  next  with  chlorine  water  and  ammonia.  The  chlo- 
roform which  adheres  to  the  mixture  of  lime  and  bark  is  displaced  by 
the  addition  of  water,  and  the  fluid  is  next  evaporated  upon  a  water- 
bath  until  a  dry  residue  is  left.  If  desired  to  save  the  chloroform,  it 
can  be  distilled  off  in  a  retort  upon  a  water-bath :  the  distillation 
should  not,  however,  be  carried  on  to  dryness,  but  the  remainder  of  the 
fluid  is  to  be  evaporated  to  dryness  in  a  porcelain  capsule,  and  then 
treated  with  dilute  sulphuric  acid.  The  solid  dry  residue  consists  of 
the  alkaloids  of  the  bark,  mixed  with  about  their  own  weight  of  waxy- 
.  resinous  {cereo  resineux)  matters  ;  the  alkaloids  are  taken  up  by  dilute 
sulphuric  acid  (1  to  10),  of  which  fluid  from  10  to  12  c.  c.  are  sufficient. 
This  solution  is  filtered  through  a  very  small,  previously  moistened, 
filter,  and  the  filtrate  is  colorless  ;  the  filtrate  is  next  heated  to  100° 
upon  a  water  bath,  and,  when  hot,  ammonia — at  first  concentrated, 
afterwards  dilute — is  added,  so  as  to  cause  the  filtrate  to  become  very 
nearly  saturated, — to  be  left  very  slightly  acid ;  all  the  quinia  will 
then  crystallize  in  the  shape  of  sulphate.  This  crystallization  pro- 
ceeds rapidly,  and  the  peculiar  odor  emitted  by  the  fluid,  as  well  as 
the  aspect  of  the  crystals,  are  of  some  value  in  ascertaining  before- 
hand the  quality  of  the  bark  operated  upon.  When  the  liquid  has 
become  completely  cold  the  crystalline  matter  forms  a  solid  cake, 
which  has  only  to  be  placed  upon  a  double  filter  for  the  purpose  of 
draining  :  the  mother-liquor  is  displaced  by  a  few  drops  of  water, 
