138 
Kernels  Quinine  Test. 
( Am.  Jour.  Phaartn, 
I      March,  1887. 
This  very  simple  experiment  furnishes  a  conclusive  answer  to  the 
objection  above  mentioned,  and  it  justifies  my  second  proposition,  that 
if  the  official  salt  is  required  to  be  completely  pure  the  Codex  test 
must  be  modified,  not  only  by  carrying  the  temperature  to  100°  C, 
but  also  by  limiting  to  nearly  about  5*5  cc.  the  volume  of  ammonia 
solution  of  0*96  that  is  to  be  added  for  the  purpose  of  rendering  the 
liquid  clear  after  precipitation. 
It  is  sufficient  to  read  the  article  in  which  the  Codex  treats  of  qui- 
nine sulphate  to  recognize  that  its  editors  have  taken  a  different  point 
of  view.  They  have  only  demanded  for  this  salt  a  relative  purity. 
This  is  evident  from  the  indications  given  for  ascertaining  "  the  pres- 
ence of  an  inadmissible  proportion  of  alkaloids  other  than  quinine." 
But  if  the  authors  of  the  official  pharmacopoeia  hesitated  to  insist  up- 
on the  complete  purification  of  an  industrial  product,  in  regard  to 
which  certain  consumers  had  themselves  acquired  usages  difficult  to 
abandon  suddenly,  they  nevertheless  very  clearly  showed,  by  the  na- 
ture and  the  number  of  the  tests  prescribed,  their  intention  to  induce 
French  pharmacists  to  exercise  increased  vigilance  in  this  particular. 
But  however  that  may  be,  a  test  admitting  of  a  certain  degree  of  tol- 
erance is  the  point  of  more  special  interest  at  the  present  moment. 
The  quinine  sulphate  of  commerce  retains  foreign  bases  in  two 
ways.  First,  the  surfaces  of  the  crystals  are  moistened  with  a  certain 
quantity  of  mother-liquor  which  imperfect  draining  has  not  removed, 
and  that  has  afterwards  dried  upon  them.  Second,  the  crystals  formed 
in  a  liquor,  charged  with  cinchonidine  sulphate,  for  example,  have  en- 
tangled some  of  the  latter  salt,  and  sometimes  a  considerable  porpor- 
tion  of  it.*  In  treating  quinine  sulphate  to  be  tested  as  Mr.  Kerner 
directs  in  one  of  the  forms  of  his  test,  with  cold  water,  the  water 
readily  becomes  charged  with  the  soluble  salts  left  by  the  mother- 
liquor  on  the  surfaces  of  the  crystals,  but  it  does  not  come  sufficiently 
into  contact  with  the  cinchonidine  sulphate  entangled  among  those 
crystals,  and  that  is  consequently  protected  from  the  action  of  the  sol- 
vent by  the  sparingly  soluble  quinine  sulphate  amongst  which  it  is  in- 
*  The  tendency  of  quinine  sulphate  and  cinchonidine  sulphate  to  crystallize 
together  is  very  marked.  When  quinine  sulphate  mixed  with  a  few  hun- 
dredths of  cinchonidine  sulphate  is  dissolved  in  boiling  water,  and  even  when 
the  volume  of  the  solvent  is  many  times  more  than  would  be  sufficient  in  the 
cold  to  dissolve  the  whole  of  the  cinchonidine  salt  if  it  were  in  a  separate 
state,  the  latter  salt  will  partially  crystallize  with  the  quinine  sulphate  during 
the  co  'ling  of  the  solution. 
