Am.  Jour.  Pharm. 
July,  1899. 
}     Acetic  Acid  in  Extracting  Drugs. 
319 
Quinine  group  .  . 
Cinchonine  group 
Other  alkaloids  . 
0*324  -=-  2  =  0*162 
0*294  -T-  4  ==  0*074 
0*312  -=-  4  ==  0*078 
Adopted  average  molecular  weight 
0-314 
This  0*314,  then,  is  adopted  as  the  factor  for  total  alkaloids  in  this 
investigation,  and  an  example  will  illustrate  its  use  in  this  paper. 
A  recent  critical  assay  of  10  grammes  of  cinchona  by  this  process 
gave  a  varnish-like  ether  extract  that  weighed  0*53  gramme,  equal 
to  5-3  per  cent,  of  crude  alkaloids.  This  indicated  (5X5  ===)  25: 
c.c.  of  decinormal  acid  required  for  dissolving  the  alkaloids.  But 
these  were  first  dissolved  in  4  c.c.  of  ether,  then  the  acid  run  in 
from  a  burette,  well  stirred  and  warmed  to  drive  off  the  ether  and 
cause  the  insoluble  matters  t6  adhere  to  the  glass. 
Into  this  solution  decinormal  alkali  was  dropped  from  a  burette 
with  stirring  until  the  neutral  point  was  reached,  as  indicated  by  the 
use  of  the  litmus  paper  strips,  when  it  was  found  that  9*3  c.c.  of 
decinormal  alkali  had  been  used.  Then  25  c.c.  of  decinormal  acid 
less  9*3  c.c.  of  decinormal  alkali  leaves  15-7  c.c.  of  the  acid  as  satu- 
rated by  the  alkaloids.    Then  the  result  is  expressed  as  follows: 
15*7  ~  10  =  1-57  x  -314  =  '49298  X  10  =  4*9  per  cent,  alkaloids. 
The  nearly  clear  solution  was  poured  . off  from  the  residue  in  the 
beaker,  and  the  residue  when  dried  weighed  0*03  gramme.  Then 
0*53  gramme  of  ether  extract  or  crude  alkaloids  less  0*03  gramme 
of  waxy  residue  left  0*50  gramme  of  alkaloids,  or  5-0  per  cent., 
against  4*9  per  cent,  by  the  titration. 
In  the  numerous  assays  of  percolates  for  the  purposes  of  this 
paper,  a  short  cut  was  found  which,  without  much  sacrifice  of  ac- 
curacy, greatly  reduced  the  time  and  labor  required,  and  seems  well 
adapted  to  pharmaceutical  use. 
Ten  c.c.  of  the  liquid  preparation  of  cinchona  is  shaken  in  a  sepa- 
rator, first  with  20  c.c.  of  the  ammonia-alcohol  mixture,  and  then 
with  30  to  40  c.c.  of  chloroform,  the  liquids  separated  as  in  the  pre- 
ceding assay  process,  which  is  then  followed  up  to  the  point  of  dis- 
solving the  chloroform  extract  in  a  fresh  portion  of  chloroform  in 
the  flask.  If  the  chloroform  extract  be  under  1  gramme,  10  c.c.  of 
fresh  chloroform  is  sufficient  for  its  solution  in  the  flask,  and  to  this 
is  added  10  c.c.  of  decinormal  acid.  The  flask  is  vigorously  shaken, 
10  c.c.  of  water  added,  the  shaking  repeated  and  the  contents 
