242 
ON  THE  CONSTITUTION  OF  QUININE. 
Without  at  first  paying  any  attention  to  the  equivalent  of  qui- 
nine—  as  Liebig  and  Regnault  agree  not  only  on  the  (per-centage) 
composition  of  it,  but  also  of  its  salts — the  question  remains  to  be 
solved,  whether  C38  H22  N2  04  or  C40  H24  N2  expresses  the  real 
composition,  and  this  may  be  done  by  experiment,  independently 
of  any  theory  whatever. 
Liebig  and  Regnault,  in  their  analyses  by  combustion,  used 
oxide  of  copper,  by  which,  however,  the  complete  combustion  of 
bodies  with  a  large  amount  of  carbon  is  unreliable;  Laurent  added 
oxygen  to  the  same.  The  analyses  of  these  three  chemists,  how- 
ever, agree  in  the  amount  of  carbon.  Some  time  ago  Wertheim 
published  that,  according  to  his  analysis,  quinine  contained  20C 
(or40C)  and  not  19C  (or  38C)  as  Laurent  thinks.  Wertheim's  ex- 
periments, however,  not  having  been  further  promulgated,  are 
therefore  useless  in  coming  to  a  decision. 
To  obtain  pure  quinine,  I  have  precipitated  sulphate  of  quinine 
by  ammonia,  washed  and  dried  the  precipitate,  treated  it  with 
ether,  until  most  of  the  quinine  was  dissolved.  The  solution  was 
evaporated,  the  residue  again  treated  with  a  little  ether,  this 
evaporated,  the  residue  dried  at  first  under  the  air-pump  and  after- 
wards at  120QC.  (248°F.)  The  combustion  was  carried  on  with 
oxide  of  copper  and  oxygen,  the  open  extremity  of  the  tube  con- 
taining metallic  copper.  The  following  were  the  results  : 
0*2912  grra.  gave  0'7905  grm.  carbonic  acid  and  0*1970  water. 
0-2798  grm.    "   0  7600  "  "         0-1890  " 
These  results  I  put  alongside  with  those  of  Liebig,  Regnault 
and  Laurent. 
^Calculated.  Obtained. 
Liebig.  Regnault.         Laurent.  •  Strecker. 
C38  73-5  G40  744  74-2  73-3  73-5     73-3  73-5    74-0  74-1 
H?2  71  H24  7-4              7-6  —  7-6       7  1   7  1     7-5   7  5 
K2  9-0   N2  8-6  8-1  —  8-5       —    —     —  — 
G4  104   04  9-9   ______ 
100-0  100-0 
My  analyses  place  beyond  any  doubt  the  formula  wTith  40C  to 
be  the  right  one,  and  the  following  experiments  give  further  evi- 
dence : 
