568 
On  Some  of  the  Tests  for  Quinine. 
/Am.  Jour.  Pharm. 
I  December,  1894. 
D.    i-iooooth  solution  of  quinine. 
1.  5  c.c.  of  the  solution  with  : 
(a)  One  drop  bromine  water  yields  a  colorless  solution, 
which  on  addition  of  a  drop  of  ammonia  quickly  assumes 
a  green  color;  this  becomes  deep  bright  green,  which 
remains  unchanged  for  many  hours. 
(p)  Two  drops  of  bromine  water  causes  a  yellow  color, 
which  is  immediately  discharged  by  a  drop  of  ammonia, 
and  the  mixture  remains  colorless. 
2.  I  c.c.  of  the  quinine  solution  fails  to  yield  a  green  coloration 
unless  the  bromine  reagent  be  diluted. 
3.  From  01  c.c.  of  the  quinine  solution,  no  green  coloration  was 
obtained,  even  with  the  diluted  bromine  reagent. 
E.    i-20000th  quinine  solution. 
5  c.  c.  of  this  solution  yields  no  green  coloration  with  the  undi- 
luted bromine  reagent;  but  under  a  dilution  of  1:2  a  well-marked 
green  color  may  be  obtained. 
From  the  foregoing  it  is  obvious  that  the  production  of  a  green 
color  under  the  action  of  this  test  depends  upon  the  presence  of  the 
quinine  and  bromine  in  proportion  contained  within  rather  narrow 
limits;  otherwise  the  green  coloration  will  not  manifest  itself. 
Should  it  be  desired  to  apply  this  test  to  only  a  small  and  limited 
quantity  of  a  suspected  solution,  it  would  be  necessary,  or  at  least 
advisable,  to  first  ascertain  under  what  conditions  a  similar  volume 
of  solution  of  quinine  of  known  strength  would  give  a  positive  reac- 
tion with  a  given  quantity  of  the  bromine  reagent,  after  proper  dilu- 
tion of  the  latter  if  necessary. 
If  an  aqueous  solution  of  chlorine,  instead  of  bromine,  be  employed 
in  the  thalleioquin  test,  a  positive  reaction  will  manifest  itself 
through  a  greater  range  than  when  bromine  is  employed,  the  result 
being  less  readily  affected  by  excess  or  deficiency  of  the  reagent. 
In  regard  to  the  production  of  a  red  coloration,  by  treating  the 
quinine  solution,  after  addition  of  .bromine  or  chlorine,  and  before 
adding  the  ammonia,  with  potassium  ferrocyanide  solution,  as  advised 
by  Vogel,  the  results  were  less  satisfactory  than  the  test  without  the 
use  of  the  potassium  salt.  With  solutions  containing  more  than 
i-ioooth  of  the  alkaloid,  a  green  or  red  or  other  coloration  may  be 
