Am.  Jour.  Pharm.  \ 
March,  1887.  j 
Kernels  Quinine  Test. 
141 
ing  consideration.  When  the  test  is  applied  without  heating,  as  the 
German  Pharmacopoeia  directs,  the  tolerance  may  amount  to  12  per 
cent.,  or  even  more  than  that. 
The  foregoing  remarks  must  be  understood  as  applying  to  the  qui- 
nine sulphate  of  commerce.  The  figures  obtained  by  various  author- 
ities with  mixtures  prepared  for  the  purpose  are  not  applicable  to  the 
mixed  crystallization  of  the  commercial  salt. 
There  are  certain  other  obj°ctions  of  secondary  importance  which 
appear  to  me  as  being  well  founded  in  reference  to  the  method  of  test- 
ing used  in  question. 
I  ha  ve  already  pointed  out  that  considerable  precision  is  required  in 
carrying  out  the  details  of  the  operation,  and  especially  in  the  meas- 
urement of  the  volumes  of  the  liquids  used. 
I  may  also  add  that  the  temperature  of  15°  C,  at  which  the  solu- 
tion has  to  be  kept  for  some  time,  is  not  always  readily  obtainable, 
especially  in  summer,  without  having  recourse  to  some  means  of  ar- 
tificial refrigeration. 
Another  small  difficulty  arises  from  the  physical  condition  of  qui- 
nine sulphate,  owing  to  which  it  mechanically  retains  the  aqueous  li- 
quid with  which  it  is  mixed,  and  does  not  always  allow  the  separation 
by  means  of  a  paper  filter  of  the  volume  necessary  for  the  treatment 
with  ammonia.  The  result  required  may,  however,  be  easily  obtained 
by  making  use  of  a  filtering  apparatus  formed  of  a  funnel  fitted  with 
a  plug  of  cotton  wool,  and  fitted  by  a  perforated  cork  into  the  neck  of 
a  tubular  flask,  so  that  the  solution  may  be  sucked  out  from  the  crys- 
tals. 
Another  point  of  more  importance  is  the  strength  of  the  amnion ia- 
cal  solution  being  precisely  regulated  to  the  requirements  of  the  test. 
If,  for  instance,  it  were  used  of  a  specific  gravity  of  0'925,  consider- 
able errors  would  result,  and  the  quinine  sulphate  represented  as  be- 
ing acceptable  for  use  under  such  conditions  would  in  reality  be  very 
impure.  It  is  therefore  impossible  to  lay  too  much  stress  upon  the 
importance  of  accuracy  in  the  preparation  of  the  ammonia  solution. 
The  Codex  has  stated  in  a  note  the  error  that  may  be  caused  by  the 
application  of  the  test  to  an  effloresced  salt.  A  pure  salt,  whether 
effloresced  or  not,  will  never  be  mistaken  for  an  impure  one  when  the 
the  test  is  applied  to  it  in  accordance  with  the  directions  of  the  Phar- 
macopoeia ;  it  may  even  be  remarked  that  if  complete  purity  had  been 
required  in  the  official  salt,  the  weighing  of  the  quantity  taken  for 
