On  Some  of  the  Tests  for  Quinine,  5^9 
developed,  the  result  depending  upon  the  relative  proportions  of 
the  reagents  employed. 
On  treating  5  c.c.  of  a  i-ioooth  quinine  solution  with  one  drop  of 
bromine  water  followed  by  one  drop  of  potassium  ferrocyanide  solu- 
tion (1:12)  and  a  drop  of  ammonia,  the  result  is  about  the  same  as 
without  the  presence  of  the  potassium  salt ;  that  is,  a  white  precipi- 
tate soon  becoming  green  is  produced.  But,  if  under  these  condi- 
tions 02  c.c.  of  the  potassium  solution  be  employed,  a  portion  of  the 
mixture  may  be  red  and  a  portion  green  in  color. 
5  c.c.  of  a  i-5000th  solution  of  the  alkaloid  under  the  action  of 
one  drop  each  of  the  reagents  as  above,  yields  a  fine  green  colora- 
tion. If,  however,  to  this  quantity  of  the  quinine  solution  one  drop 
of  bromine  water  be  added  and  then  0-5  c.c.  of  the  ferrocyanide  solu- 
tion, the  mixture,  without  the  addition  of  ammonia,  immediately 
assumes  a  deep  red  color.  If  a  drop  of  ammonia  be  now  added, 
the  red  color  quickly  changes  to  a  beautiful  purple. 
5  c.c.  of  a  i-iooooth  quinine  solution  with  one  drop  each  of  the 
reagents,  yields  a  fine  red -purple  coloration  which  soon  changes  to 
green. 
5  c.c.  of  a  i-20000th  solution,  under  like  conditions,  yields  a  fine 
red  coloration,  which  quickly  fades  to  a  light  yellow  color. 
2.    HERAPATHITE  TEST 
This  test  was  first  proposed  by  Dr.  Herapath,  in  1852,  and  con- 
sists in  the  formation  of  quinine  iodosulphate  or  Herapathite,  as  it 
has  been  termed.  This  compound  may  be  obtained  by  treating  a 
solution  of  quinine  in  a  mixture  of  strong  acetic  acid  and  alcohol, 
with  an  alcoholic  solution  of  iodine.  In  a  little  time  the  iodosul- 
phate separates  out  in  the  form  of  characteristic  plates  and  rosette 
groups  of  crystals.  By  reflected  light,  the  crystals  are  of  a  dark 
green  color;  under  transmitted  light  they  are  dichroic  and  strongly 
polarize  light. 
The  reagents  may  be  prepared  as  follows  :  (a)  Thirty  volumes 
of  strong  acetic  acid  are  mixed  with  ten  volumes  of  strong  alcohol 
and  one  volume  of  diluted  sulphuric  acid  (1:10).  (b)  One  part  of 
iodine  is  dissolved  in  about  twenty  parts  by  weight  of  alcohol. 
To  apply  the  test,  a  drop  of  the  quinine  solution  is  evaporated  to 
dryness,  and  the  residue  treated  with  a  drop  of  the  first-mentioned 
solution ;  a  minute  drop,  or  sufficient  to  color  the  liquid  brownish- 
