108  Researches  on  the  Cinchona  Alkaloids.  {^'^mlvl\^\.'^' 
homocinchoiiidia  and  cinchonia  contain  each  a  hydroxyl  group,  it  was 
further  to  be  determined  whether,  by  the  action  of  highly  concen- 
trated hydrochloric  acid,  as  applied  by  Zorn,  a  further  decomposition 
or  perhaps  molecular  change  of  the  respective  alkaloids  did  not  precede 
the  reaction  in  view.  The  author  has  previously  shown  how  easily  the 
quinia  disulphate  passes  into  quinicia  salt,  the  cinchonidia  disulphate 
into  cinchonicia  salt,  etc.;  and  the  further  observation  was  made,  that 
by  the  action  of  hydrochloric  acid  on  quinamina,  according  to  the  con- 
centration of  the  acid  and  other  circumstances,  quite  different  results 
are  obtained,  which  should  be  more  closely  considered.  It  was,  indeed, 
found  that  the  alkaloids  in  question — quinia,  cinchonidia  and  their 
isomers — cannot  resist  the  action  of  hydrochloric  acid,  spec.  grav. 
1*25,  but  that  when  subjected  to  this  treatment  in  sealed  tubes  at  140^ 
to  150°C.  for  from  6  to  10  hours,  a  molecular  change  takes  place? 
whereby  at  the  same  time,  in  the  case  of  quinia  and  quinidia,  chloride 
of  methyl  is  formed ;  the  latter  partially  condenses  under  the  pressure 
produced  in  the  tube  to  a  mobile,  strongly-refractive  liquid,  which, 
upon  opening  the  tube,  becomes  immediately  dissipated.  As  the  for- 
mation of  the  chloride  of  methyl  repeatedly  resulted  in  the  explosion 
of  the  tubes,  it  was  considered  advisable  not  to  employ  more  than  2 
grams  of  quinia  or  quinidia  hydrochl orate  with  about  10  cc.  of  hydro- 
chloric acid  for  each  tube,  and  further,  to  cool  the  tubes  well  with  ice 
before  opening.  With  cinchonidia,  homociiiclionidia  and  cinchonia 
this  precaution  was  not  necessary,  as  after  heating  not  the  slightest 
pressure  was  found  in  the  tubes ;  and  for  these  alkaloids,  therefore, 
a  larger  amount  (4  grams  to  12  or  15  cc.  acid  for  each  tube)  were 
employed  for  the  reaction.  By  this  treatment  there  are  produced, 
without  the  formation  of  other  substances, 
from  Quinia  and  hydrochloric  acid  :  Apoquinia  and  chloride  of  methyl, 
from  Q  uinidia  and  hydrochloric  acid  :  Apoquinidia  and  chloride  of  methyl, 
from  Cinchonidia  "  "    :  /?Cinclionidia  and  apocinchonidia, 
from  Homocinchoiiidia "  "    :  Apocinchonidia, 
from  Cinchonia  "  "    :  Aj^ocinchonia  and  diapociiiclionia. 
Apoquinia,  ^^^22^2^2  (anhydrous). — The  acid  solution  is  diluted 
with  cold  water,  gradually  precipitated  by  ammonia,  the  voluminous, 
flocculent,  yellowish- white  precipitate  is  washed  with  a  little  cold 
water,  dissolved  in  acetic  acid  and  treated  with  animal  charcoal.  After 
the  brownish-yellow  color  has  changed  to  a  bright  yellow  the  solution 
gives,  upon  the  addition  of  excess  of  ammonia,  a  white  flocculent  pre- 
cipitate, which,  after  washing  with  cold  water,  dries  in  the  form  of  white, 
