142 
Kernels  Quinine  Test. 
( Am.  Jour,  Pharm. 
\      March,  1887. 
testing  would  have  been  superfluous,  for  the  solution  after  recrystalli- 
zation  at  15°  C.  ought  always  to  give  a  clear  liquid  on  the  addition  of 
ammonia,  however  much  of  the  salt  was  operated  upon.  But  since  a 
certain  tolerance  is  allowed  for  the  manufacture  the  case  is  altered  in 
this  respect.  If  the  sulphate  has  lost  by  efflorescence  some  part  of  the 
water  which  it  should  contain  in  the  normal  condition,  one  gram  of  it 
will  represent  a  proportionally  larger  quantity  of  the  fully  hydrated 
salt ;  the  impurity  passing  into  solution  would  thus  be  increased  hi 
quantity  and  the  tolerance  diminished.  In  such  a  case  the  best  plan 
is  to  dry  the  salt  completely  at  100°  C,  and  to  take  a  quantity  weigh- 
ing *8555  gram  instead  of  one  gram,  as  the  Codex  recognizes  that  the 
salt  should  contain  14'45  per  cent,  water  of  crystallization.  At  the 
same  time  it  should  not  be  forgotten  that  in  efflorescing,  the  crystals 
undergo  a  disintegration  which  renders  the  material  especially  fit  to  be 
acted  upon  by  water  as  a  solvent,  and  this  will  tend  to  diminish  the 
tolerance. 
Recently  Kremel  has  pointed  out  a  possible  modification  of  Kerner's 
test,  based  upon  the  circumstance  that  the  solutions  of  the  sulphates  of 
cinchona  alkaloids  saturated  at  a  temperature  of  15°  C.  contain  differ- 
ent quantities  of  these  salts  as  folloAvs  : — 
5  cc.  of  solution.  Contain 
Quinine  Sulphate   0'0062  gram  of  the  salt. 
Quinidine      "    '0464 
Cinchonidine  "    '0510 
Cinchonine    "    "0925 
Consequently,  the  same  measure  of  the  solutions  also  contain  very 
different  quantities  of  sulphuric  acid,  and  as  the  alkaloids  in  question 
do  not  react  upon  phenophtalein  it  is  possible  to  titrate  the  sulphuric 
acid  in  a  solution  of  quinine  sulphate,  with  an  alkaline  solution  as  well  as 
if  it  was  in  a  free  state.  The  quantity  of  sulphuric  acid  found  in  a 
solution  of  pure  quinine  sulphate  would  be  very  much  less  than  in  a 
solution  of  an  impure  sample,  and  in  this  way  the  amount  of  impurity 
might  be  ascertained. 
The  sources  of  errors  already  referred  to  as  being  inseparable  from 
the  preparation  of  the  solution  saturated  at  15°  C.  from  the  commer- 
cial quinine  sulphate  would  obviously  exercise  the  same  kind  of  in- 
fluence upon  results  obtained  by  the  method  proposed  by  Kremel  as 
upon  those  obtained  by  the  method  of  the  Codex.  A  further  error 
would  also  be  made  by  taking  the  quantity  of  sulphuric  acid  as  being 
