408 
Quinine  Testing. 
(  Am.  Jour.  Pharm. 
\      August.  1887. 
quinine  sulphate.  On  the  basis  of  my  long  experience  of  this  sub- 
ject, I  proposed  to  the  Pharmacopoeia  Commission  in  1882  not  only  a 
test  which  would  without  difficulty  admit  of  the  detection  of  a  small 
admixture  of  cinchonidine  sulphate,  but  also  sent  a  report  that  was 
read  by  the  late  Professor  Fehling  at  a  meeting  of  the  Commission, 
in  which  I  fully  discussed  the  whole  subject,  and  pointed  out  the 
defects  of  the  test  in  the  Pharmacopoeia.  Notwithstanding  this,  only 
Professors  Fehling  and  Otto  were  in  favor  of  my  test  being  adopted, 
all  the  other  members  preferring  to  adopt  Kerner's  test  on  the  recom- 
mendation of  Professor  Fliickiger,  although  I  had  shown  in  my 
report  that  with  quinine  sulphate  that  is  not  effloresced,  or  only  par- 
tially so,  a  large  portion  of  the  cinchonidine  sulphate  present  would 
escape  detection  by  that  test. 
In  reply  to  the  objection  raised  by  Vulpius  to  my  proposed  test, 
that  I  desired  to  pass  a  less  pure  quinine  sulphate  than  the  Pharma- 
copoeia and  the  German  pharmacists  required,  I  can  therefore  refer  to 
these  facts  as  proving  that  his  opinion  in  that  respect  is  entirely 
unfounded. 
The  test  proposed  by  me  was  as  follows  : 
Take  1  gram  of  the  quinine  sulphate  dried  at  100°  C,  shake  it 
with  20  c.c.  of  water  at  60°  C,  filter  after  cooling,  and  place  5  c.c.  ot 
the  filtrate  in  a  narrow  test  tube  with  5  c.c.  of  ether  and  5  drops  of 
ammonia  solution ;  close  the  tube  and  shake  the  mixture.  The  dear 
ether  solution  thus  obtained  should  not  afterwards  deposit  crystals. 
The  settlement  of  the  point  as  to  the  time  to  be  allowed  for  such  a 
deposit  to  take  place  I  left  to  the  Commission ;  also  the  decision 
whether  quinine  sulphate  with  two  or  more  per  cent,  of  cinchonidine 
.salt  was  to  be  passed. 
It  will  be  seen  that  this  test  was  very  similar  to  that  I  had  pre- 
viously recommended  ;  it  was  simply  an  improvement  upon  that  by 
which  I  had  done  away  with  defects  of  which  I  had  become  aware  by 
long  experience. 
The  principle  on  which  this  test  is  based  is  the  fact,  unfortunately 
still  insufficiently  known,  that  the  compound  of  cinchonidine  sulphate 
with  quinine  sulphate  is  decomposed  at  100°  C,  and  in  a  certain  way 
disintegrated,  so  that  the  whole  of  the  cinchonidine  sulphate  present 
is  acted  upon  and  dissolved  by  the  water  used.  Although  in  contact 
with  water  a  partial  combination  of  the  associated  sulphates  may  be 
induced,  by  far  the  greater  part  of  the  cinchonidine  sulphate  passes 
