418 
ALKALOIDS  IN  THE  CINCHONA  BARKS. 
— that  there  are  alkaloids  in  the  cinchona  barks,  which,  although 
isomeric,  and  partly  also  isomorphous  with  the  ordinary  quini- 
dine,  still  exhibit  many  abnormal  chemical  properties,  amongst 
which  I  may  especially  mention  a  very  different  (far  greater) 
degree  of  solubility  in  ether.  I  made  experiments  with  the 
sulphates  of  these  quinidine  bases  which  were  more  soluble  in 
ether,  and  found  that  from  ten  to  twenty  per  cent,  of  these 
salts  could  be  mixed  with  the  pure  sulphate  of  quinine  without 
being  detected  by  the  ether-test ;  and  it  is  to  be  feared  that 
manufacturers  may  make  use  of  this  property  of  the  new  alka- 
loids to  enable  them  to  sell  under  the  protection  of  the  ether- 
test  an  inferior  sulphate  of  quinine  mixed  with  other  cheaper 
sulphates.  Now  it  would  be  quite  possible  to  detect  an  exten- 
sive adulteration,  when  once  known,  by  other  means  (ex.  gr.  by 
treating  the  alkaloids  precipitated  from  the  mixed  sulphates 
with  spirits  of  wine  of  20°  Beaume;)  but  it  would  be  exceed- 
ingly difficult,  nay,  even  impossible,  qualitatively  to  detect,  by 
means  of  this  test,  smaller  unintentional  adulterations  (impuri- 
ties.) I  therefore  set  to  work  to  find  out  a  quinine  test  which 
would  be  both  accurate  and  easy  of  execution,  and  by  which  it 
would  be  possible  to  detect  even  very  small  quantities  of  the 
above  new  bases. 
Before  I  enter  upon  the  description  of  the  experiments  made 
for  this  purpose,  I  may  be  permitted  to  give  a  short  sketch  of 
the  characteristic  properties  of  the  cinchona  alkaloids  in  general, 
on  account  of  the  confusion  in  their  nomenclature  which  pre- 
vails among  chemists.  A  few  remarks  on  this  subject  may, 
therefore,  be  acceptable  in  this  place.  Chemists  who  have  had 
an  opportunity  of  studying  the  cinchona  bases  must  have  ob- 
served that  quinine,  cinchonine,  quinidine,  and  cinchonidine  are 
not  the  only  bases  found  in  the  barks,  but  that  frequently  modi- 
fications of  these  principal  bases  are  met  with  in  the  cinchona 
barks,  which  differ  in  many  essential  points  from  them.  I  be- 
lieve, however,  that  all  organic  bases  derived  from  the  barks 
(whether  known  or  not  yet  known,)  may  be  conveniently  ar- 
ranged into  two  distinct  groups  until  science  succeeds  in  un- 
ravelling the  true  constitution  of  these  substances,  viz  : — 
I.  Group. — Quinine  and  its  isomerides,  of  the  formula  C^H^ 
Na04+sHO. 
