Am.  Jour.  Pharm.  t 
•  July,  1892.  J 
Assay  of  Nnx  Vomica. 
339 
highest  result  should  be  taken  as  the  standard.  This  I  believe  is 
not  always  warranted.  We  have  as  yet  much  to  learn  concerning 
the  amount  of  true  crysiallizable  or  active  alkaloids  in  some  of  these 
crude  amorphous  residues.  Where  the  work  is  checked  by  testing 
of  residues  to  show  complete  abstraction  of  alkaloid,  for  alkaloids 
that  do  not  wear  out  in  manipulation,  the  lowest  result  would  prob- 
ably indicate  the  nearest  true  average. 
The  method  of  assay  suggested  herein  need  not,  in  its  application, 
require  the  personal  attention  of  an  expert  chemist,  the  chief 
chance  for  variation  being  in  the  drying  and  weighing  of  the  final 
residue,  which  is  not  confined  to  this  method,  but  occurs  alike  with 
all  gravimetric  schemes.  Many  of  the  evaporations  of  the  following 
experiments  were  made  in  deep  platinum  dishes  and  these  were  most 
satisfactory,  although  unnecessary  for  approximate  valuations. 
Notwithstanding  such  experimental  variations,  which  exist  even 
with  absolutely  pure  alkaloids,  the  gravimetric  method  seems  pre- 
ferable to  the  volumetric  by  reason  of  the  difficulty  of  establishing 
the  end  reaction  with  alkaloidal  reagents.  One  of  the  pressing 
desideratums  of  this  day  is  that  of  a  delicate  alkaloidal  color 
indicator. 
Process. — The  process  may  be  divided  into  sections,  as  follows : 
TO  ASSAY  FLUID  EXTRACT  OF  NUX  VOMICA.1 
(i)  Into  the  graduate  pour  5  cc.  Fluid  Extract  of  Nux  Vomica 
and  10  cc.  of  Chloroform,  then  add  8  grams  of  Iron  Mixture,2 
stir  together,  and  add  Glucose  Mixture3  (from  2  to  4  cc.)  enough  to 
form  a  pulp. 
Stir  briskly  and  decant  the  chloroform  into  a  beaker  glass,  then 
successively  wash  the  magma  with  two  portions  of  chloroform,  each 
10  cc,  decanting  each  into  the  beaker.  Should  the  magma  adhere 
to  the  sides  of  the  graduate  above  the  stirrer,  scrape  it  down  occa- 
sionally by  means  of  the  spatula  side  of  the  stirrer. 
Evaporate  the  chloroform,  pour  upon  the  residue  6  cc.  dilute  (1 
to  49  by  measure)  sulphuric  acid,  warm  gently  and  filter  through  a 
1  This  process  without  the  mechanical  mixer  was  the  one  I  suggested  to 
Prof.  Norton,  and  which  was  employed  in  the  University  of  Cincinnati  deter- 
minations.   (See  Journ.  Anal,  and  Applied  Chemistry,  March,  1892.) 
2  Equal  amounts  of  dry  ferric  hydrate  and  sodium  bicarbonate,  mixed. 
3  Equal  measures  of  glucose  and  water. 
