626  Extraction  of  Alkaloids  from  Cinchona.      { ^'"■pec^^JS!™ ' 
of  the  alkaloids  at  a  high  temperature  much  more  difficult,  and  is 
unattended  with  any  advantages. 
I  have  been  thus  minute  in  discussing  the  treatment  of  cinchona 
bark  by  dilute  acids  for  two  reasons,  viz : 
1.  Because  the  extraction  of  the  alkaloids  from  bark  by  hydrochlo- 
ric acid  has  been  extensively  practiced  in  Bengal  since  1872  in  the 
manufacture  of  the  well-known  cinchona  febrifuge  (sometimes  called 
Indian  quinine  and  the  process,  which  was  adopted  on  my  recom- 
mendation to  the  Secretary  of  State  for  India,  has  been  condemned  as 
wasteful  by  the  editor  of  the  "  Pharmaceutical  Journal."  ^ 
2.  Because,  as  an  old  pharmacist,  I  wish  all  pharmacists  to  examine 
for  themselves  the  quality  of  the  cinchona  bark  that  they  use,  and  I 
consider  the  hydrochloric-acid  process  by  far  the  most  suitable  for 
j)harmaceutical  uses.  It  is  simple,  inexpensive,  thoroughly  reliable, 
iind  practically  (if  not  scientifically)  accurate.  It  is  also  capable  of 
indicating  not  only  the  percentage  of  alkaloids,  but  also  the  proportion 
of  cinchotannic  acid,  which  is  of  no  small  importance  from  a  thera- 
peutical point  of  view. 
Tht  following  directions  will  enable  pharmacists  to  obtain  satisfac- 
tory results  with  facility: 
Mode  of  Ancdyzing  Cincliona  Bark  by  Hydrochloric  Acid. 
Twenty  grammes  of  finely-powdered  bark  are  treated  with  hydro- 
chloric acid  and  water  as  above  described,  whereby  all  the  alkaloids  are 
dissolved.  The  quantity  of  percolate  which  it  is  necessary  to  pass 
through  the  marc  is  usually  from  180  cc.  to  200  cc,  which  quantity 
will  rarely  be  exceeded  if  the  percolation  has  been  successfully 
conducted.  The  estimation  of  the  amount  of  alkaloids  in  this  acid 
solution  may  be  made  in  either  of  the  following  ways,  viz: 
1.  The  acid  solution  is  precipitated  by  a  large  excess  of  caustic  soda, 
which  throws  down  a  curd-like  white  precipitate.  The  precipitate  is 
collected  on  a  double  filter,^  and  washed  until  the  filtrate  is  nearly 
colorless.  The  whole  of  the  filtrate  is  measured,  and  compensation 
made  by  adding  to  the  weight  of  alkaloid,  to  be  presently  ascertained, 
0'0585  gramme  for  every  100  cc.  of  the  mother-liquor  at  temperature 
15°C.  The  drained  filter  is  carefully  dried  upon  blotting-paper  until 
^he  precipitate  ceases  to  adhere,  when  it  may  be  easily  detached 
1  "  Pharmaceutical  Journal,"  September  13,  1884,  p.  205. 
'  Doubling  the  filter  facilitates  the  filtration. 
