364  Note  on  the  Cinchona  Alkaloids.  {^"jijy'iss?'"'"" 
I  cannot  conclude  this  communication  without  first  briefly  referring 
to  two  other  cinchona  alkaloids. 
The  first  is  homoquinine,  which  was  found  simultaneously  in  cuprea 
bark  by  D.  Howard  and  J.  Hodgkin  ("  Phar.  Jour/'  [3],  xii,  528.), 
E.  H.  Paul  and  A.  J.  Cownley  (^^bid.''  [3],  xii,  497),  and  G.  Whiffen 
("Ibid."  [3],  xii,  497)  (see  "Am.  Jour.  Phar.,''  1882,  p.  75).  According 
to  Herr  J.  A.  Tod,  who  observed  the  alkaloid  as  far  back  as  the  autumn 
•of  1880,  this  bark  contains  it  very  frequently,  often  to  the  extent  of 
nearly  0*3  per  cent. 
For  the  material  used  in  my  investigation  I  am  indebted  to  Herr 
Tod,  who  occasionally  obtained  it  in  his  examinations  of  cuprea  bark. 
The  substance  was  purified  by  repeated  recrystallizations  from  ether. 
When  dried  at  120°C.  its  composition  corresponded  to  the  formula 
Calculated,  Found. 
C,    .  .  .  73-54       73-67  73*16 
H,         .  .  .      7-09        7-35  7-09 
Homoquinine  crystallizes  from  ether  containing  water,  partly  in  flat 
prisms  and  partly  in  laminae.  The  former  contain  2  molecules  of  water 
of  crystallization,  the  latter  apparently  only  1  molecule. 
Calculated.  Found. 
Prisms,     2H2O,  10-44       10-88  10*40  lO'OO 
Scales,       H2O,  5-49  6-54 
Homoquinine  melts  at  177°C.  (uncorr.);  it  dissolves  freely  in  alco- 
liol  and  chloroform,  and  sparingly  in  ether,  from  which  it  crystallizes 
in  proportion  as  it  can  take  up  water.  If  dehydrating  substances  are 
present,  it  can  apparently  only  be  obtained  amorphous.  It  dissolves 
in  dilute  sulphuric  acid  with  blue  fluorescence,  and  with  chlorine  and 
excess  of  ammonia  is  colored  exactly  the  same  as  quinine. 
Homoquinine  gives  with  several  acids  easily  crystallizable  salts,  the 
aqueous  solutions  of  which  yield  with  potassium  iodide  only  a  resinous 
precipitate.  Its  sulphuric  acid  solution  immediately  decolorizes 
potassium  permanganate. 
The  neutral  tartrate  crystallizes  in  colorless  needles,  which  are  spar- 
ingly soluble  in  cold  water. 
The  neutral  sulphate,  {Q^^^^fi^^^^OJi^'^^^'z^jij  crystallizes  in 
short  prisms,  which  are  very  sparingly  soluble  in  cold  water  and  readily 
efiloresce.  (Found  12*50  and  13*37  per  cent.  Hp ;  calculated  13-07 
percent.)  Since  in  respect  to  solubility  in  water  this  salt  resembles 
almost  exactly  quinine  sulphate,  the  possibility  is  not  excluded  that  it 
