156  Chemical  Examination  of  Cincho-^inine,\^'^-^°^;^^^^""'- 
faint  green  color  with  chlorine  water  and  ammonia,  and  a  faint  red  color, 
with  chlorine  water,  ferrocyanide  of  potassium  and  ammonia. 
Result  of  b. — Traces  of  quinia,  or  quinidia,  or  both,  are  contained 
in  the  residue  b. 
RECAPITULATION   OF   RESULTS  D. 
The  various  samples  of  cinch o-quinine  examined  by  us^  yield  a  considerable 
percentage  to  cold  water.  The  solutions  yield  upon  evaporation  white crystalline 
residues^  which.,  as  proven  by  experiment  D  2,  upon  the  residue  from  sample 
No.  4,  {which  had  yielded  to  water  22  per  cent,  of  its  components).,  are  com- 
posed mainly  of  sulphate  of  cinchonia^  and  contains  only  traces  of  quinia^  or 
quinidia.,  or  both.,  probably  as  sulphates. 
EXPERIMENTS  E. 
E  I. — 2'0  grams  each,  of  samples  No.  i.  No.  3,  and  No.  4,  were 
severally  dissolved  in  acidulated  water,  the  solutions  precipitated  by  am- 
monia, the  precipitates  collected,  washed,  dried,  and  shaken,  occasion- 
ally for  24  hours,  with  i\  fluidounce  of  strong  ether;  the  filters,  care- 
fully torn  into  shreds,  being  introduced  into  the  flasks,  along  with  the 
finely  powdered  precipitates.  The  contents  of  the  flasks  were  finally 
thrown  on  a  filter,  and  the  residue  in  the  filters  washed  with  sufficient 
stronger  ether  to  make  each  filtrate  measure  ij  fluidounces.  These 
filtrates  were  evaporated  in  tared  beakers,  first  spontaneously,  and  after- 
wards, until  completely  dry,  on  a  water  bath.  The  following  table,  in 
which  we  include  the  result  obtained  with  the  sample  No.  2,  as  detailed 
in  our  experiment  B  i,  will  show  the  results  of  our  experiment  E  i  : 
CINCHO-QUININE. 
QUANTITY  USED. 
AMOUNT  OF  RESIDUE 
FROM  ETHE- 
REAL SOLUTION. 
PERCENTAGE. 
Sample  No.  i. 
2  grams. 
0-098  grams. 
4  90  per  cent. 
Sample  No.  2. 
5  grams. 
0*256  grams. 
5-13  per  cent. 
Sample  No.  3. 
2  grams. 
0'o8i  grams. 
4-05  per  cent. 
Sample  No.  4. 
2  grams. 
o'loo  grams. 
5'Oo  per  cent. 
In  the  ethereal  residues  of  samples  No.  i  and  No.  4,  we  concluded 
to  determine  the  quinia  by  a  method,  which  is  based  on  the  relative 
solubility  of  the  alkaloids,  quinia  and  quinidia,  in  water,  and  which 
seemed  to  us  to  lead  to  the  most  satisfactory  results.  If  we  digest  a 
mixture  of  quinia  and  quinidia  on  a  water  bath  with  water,  and  allow 
