ii4 
Assay  of  Belladonna  Leaves. 
Am.  Jour.  Ptiarm 
March,  1899. 
To  ascertain  the  cause  of  the  discrepancy  between  the  theoretical 
and  found  percentages  of  alkaloid  in  the  extract  a  series  of  assays 
were  made  with  a  purchased  sample  of  powdered  belladonna  leaves 
manipulating  as  described,  but  changing  the  quantities  of  drug^ 
solvent  and  water  as  shown  in  the  following  arrangement : 
a 
b 
j* 
d* 
e 
10  gm. 
10  gm. 
20  gm. 
20  gm. 
Ether  
100  " 
100  " 
100  " 
60  " 
25  " 
25  " 
25  " 
15  " 
Ammonia  water  (iop.  c.)  . 
.   .10  c.c. 
10  c.c. 
5  c.c. 
10  c.c. 
10  c.c. 
20  " 
15  " 
30  « 
10  " 
Time  of  maceration    .  .  . 
4  hrs. 
4  hrs. 
2  hrs. 
2  hrs. 
2  hrs. 
.  0*414  p.c. 
0*468  p.c. 
0-418  p.c. 
0-383  p.c. 
0-399  P-1 
*  A  fifth  portion  of  ether-chloroform  of  20  c.c.  used  to  ascertain  if  the  extrac- 
tion was  complete  ;  the  residue  from  this  extraction  failed  to  cause  an  alkaline 
reaction  with  the  indicator. 
These  results  are  very  discordant  and  indicate  that  the  time 
allowed  for  maceration  (it  should  be  recalled  that  the  original  pro- 
cess required  but  a  half  hour's  maceration)  and  the  quantity  of 
aqueous  solution  compared  with  the  quantity  of  alkaloidal  solvent 
are  important  factors  in  the  yield  of  alkaloid.  This  last  factor  being 
realized,  and  it  is  remembered  that  the  first  operation  in  the  assay 
is  practically  the  same  as  the  third  operation  (removing  the  alka- 
loid from  ammoniacal  solution  by  the  alkaloidal  solvent),  we  can 
see  where  error  is  likely  to  be  introduced.  In  the  first  operation  it 
is  assumed  that  the  ether-chloroform  used  contains  all  of  the  alkaloid 
and  that  the  aqueous  solution  is  simply  used  to  moisten  and  agglu- 
tinate the  drug  into  lumps  so  as  to  assist  separation  of  the  alkaloidal 
solution  ;  in  the  third  operation  three  portions  of  solvent  are  used 
to  complete  the  extraction  of  the  alkaloid.  It  would  be  a  parallel 
case  if  in  the  third  operation  a  larger  quantity  of  solvent  were  used 
and  an  aliquot  portion  of  this  taken  to  complete  the  assay.  To 
prove  what  is  stated,  20  grammes  of  the  leaves  were  percolated  with 
300  c.c.  alcohol  (95  per  cent.)  in  a  manner  to  be  described  later 
(page  1 16),  the  percolate  evaporated  at  a  temperature  not  exceeding 
500  C.  and  the  extract  obtained  assayed,  as  previously  described. 
The  drug  exhausted  by  95  per  cent,  alcohol  was  next  percolated 
in  the  same  manner  with  200  c.c.  of  a  menstruum,  consisting  of  alco- 
hol 2  volumes,  and  water  1  volume  ;  the  percolate  was  evaporated 
and  assayed  as  stated  above.    Finally,  the  drug  exhausted  with  the 
