4 
Estimation  of  Strychnine  in  Nux  Vomica. 
(  Am.  Jour.  Pharm. 
I    January,  1907. 
Result :  Bright-red  mixture  giving  at  the  end  of  ten  minutes  no 
reactions  for  alkaloids. 
Experiment  (b).  The  solution  of  brucine  was  rotated  while  the 
nitric  acid  mixture  was  being  added,  so  as  to  thoroughly  mix  the 
acids  immediately  on  coming  in  contact. 
Result :  Water- white  mixture  which  had  a  faint  yellow  tinge  after 
24  hours. 
Brucine  recovered  at  end  of  that  time  0-91  gramme,  i.  e.,  91  per 
cent. 
Experiment  (c).  The  nitric  acid  mixture  was  added  in  a  hap- 
hazard manner  and  beaker  rotated  as  directed  in  the  official  process. 
Results :  Various,  usually  the  mixture  remained  colorless,  some, 
times  it  became  red. 
Farr  and  Wright  suggested  heating  the  solution  of  alkaloids  to 
1220  F.  before  adding  the  nitric  acid.  Accordingly  these  experi- 
ments were  repeated  at  that  temperature. 
The  results  were  the  same  as  before  ;  experiment  (#)  gave  a  red 
liquid;  (b),  a  colorless  mixture  which  remained  so  over  night,  and  (c) 
a  mixture  red  or  colorless,  as  luck  would  have  it. 
The  foregoing  experiments  were  repeated,  using  different  samples 
of  nitric  acid ;  those  containing  traces  of  hyponitric  acid  affected 
the  brucine  much  more  readily  than  an  acid  strictly  pure. 
Kebler  and  Hoover  found  traces  of  this  impurity  in  two  out  of 
four  samples  of  CP.  nitric  acid  they  examined.9 
Besides  the  various  methods  of  adding  the  nitric  acid,  the  absence, 
or  varying  proportion,  if  present,  of  the  lower  oxides  of  nitrogen 
may  possibly  account  for  the  astonishing  lack  of  uniformity  in  the 
results  of  different  operators.  The  presence  of  the  lower  oxides  of 
nitrogen  in  nitric  acid,  either  as  an  impurity  or  as  the  first  product 
of  the  reaction,  is  often  necessary  to  start  the  nitration  of  organic 
compounds.  In  the  experiment  {a)  by  allowing  the  strong  nitric 
acid  to  remain  in  contact  with  the  brucine  solution  this  desideratum 
is  obtained.  It  seemed  reasonable  to  infer  from  this,  that  if  the  pre- 
liminary reduction  of  the  nitric  acid  were  prevented,  the  production 
of  di-nitro-brucine  would  not  take  place.  Accordingly  a  few  drops 
of  hydrogen  peroxide  solution  were  added  to  a  portion  of  the  acid 
solution  of  brucine,  and  the  strong  nitric  acid  mixture  was  trickled 
9  U.  S.  Dept.  of  Agriculture,  Bureau  of  Chemistry,  Bulletin  99,  page  191. 
