ALKALOIDS  IN  THE  CINCHONA  BARKS. 
419 
II.  Group. — Cinchonine  and  its  isomerides,  of  the  formula 
C40H24N2O2. 
This  classification  does  not  comprise  some  of  the  more  ob- 
scure bases,  whose  formulae  require  further  confirmation  before 
they  can  be  accepted  as  forming  part  of  Groups  I.  and  II.  of 
alkaloids,  or  whose  derivation  from  cinchonas  is  doubtful  (ex.  gr. 
aricine,  paracine,  cinchovatine,  pitayine,  blanchinine,  Gruner's 
bases,  etc.) 
I.  Group. — The  solutions  of  salts  of  these  bases  give,  in  every 
instance,  the  well-known  reaction  with  chlorine  water  and  am- 
monia. The  pure  alkaloids  form  hydrates,  which  effloresce 
readily. 
1.  Quinine  (forming  crystallizable  salts.)— When  pure  it  is 
generally  amorphous,  forms  however  two  hydrates,  with  two  and 
six  equivalents  of  water.  Besides  many  distinctive  properties 
which  its  compounds  with  organic  and  inorganic  acids  possess, 
it  is  distinguished  at  once  by  a  property  which  singles  it  out 
from  among  all  the  cinchona  bases,  viz.,  the  property  of  forming 
a  crystallizable  product  of  substitution  with  iodine, — the  highly  in- 
teresting Herepathite.  By  the  aid  of  the  microscope  Herepath's 
reaction  enables  us  also  to  ascertain  whether  a  commercial  qui- 
nine salt  contains,  besides  quinine,  traces  of  other  alkaloids,  or 
crystallizable  extractive  matter  {salicine,  phlorhidzine.)  This 
reaction  requires,  however,  great  practice. 
2.  Quinoidine. — An  amorphous  modification  of  the  quinine,  to 
which  it  stands  probably  in  a  similar  relation  to  that  of  grape 
to  cane  sugar.  If  Pasteur's  observation  of  a  product  of  decom- 
position produced  by  the  action  of  sulphuric  acid  upon  quinine 
is  at  all  correct,  quinoidine  invariably  contains  quinicine. 
3.  Ordinary  Quinidine  Quinidine.) — The  sulphate  of  qui- 
nidine  most  frequently  (at  least  formerly)  met  with  is  the  sul- 
phate of  *  quinidine.  It  is  of  a  very  different  solubility  in  cold 
water — from  1  part  in  300  to  1  part  in  180,  rarely  more.  The 
pure  alkaloid  crystallizes  from  spirit  in  large,  short,  slowly 
efflorvescing,  truncated  prisms.  Tepid  ether  dissolves  mere 
traces  of  the  base,  which  crystallize  out  on  standing  for  a  short 
time.  Its  presence  in  sulphate  of  quinine  is,  therefore,  readily 
indicated  by  the  ether-test.  Many  of  its  salts  exhibit,  when 
compared  with  the  corresponding  quinine  salts,  striking  differ- 
