164  Researches  on  the  Cinchona  Alkaloids.  {^"Apnr'i^ssr"*' 
alkaloid  forms  apparently  only  acid  salts,  of  which  only  the  dichlor— 
hydrate  and  the  ehloroplatinate  were  more  closely  examined.  The 
former  is  in  small,  colorless,  six-sided  scales,  which  in  a  certain  position 
appear  dicliroic,  dissolve  quite  readily  in  water,  but  very  difficultly  in 
moderately  strong  hydrochloric  acid  and  in  alcohol,  and  contain  no 
water  of  crytallization.  The  chlofoplatinate  is  a  flocculent  precipitate,, 
changing  into  glossy  orange-colored  crystals. 
Hydrochlorapocmchonidia,  C19H23CIN2O. — As  already  stated  this 
alkaloid  is  formed  by  the  action  of  highly  concentrated  hydrochloric 
acid  upon  apocinchonidia,  and,  therefore,  also  from  cinchonidia,  /9cin- 
chonidia  and  homocinchonidia,  as  these  by  treatment  with  hydrochloric- 
acid  are  first  transformed  into  apocinchonidia.  Zorn  believed  to  have 
obtained  at  once  the  pure  base  by  the  precipitation  of  the  acid  solution 
with  ammonia;  the  results  obtained  by  the  author  in  about  twenty 
experiments  were  unsuccessful,  a  certain  amout  of  apocinchonidia  being- 
always  present.  If  the  contents  of  the  tubes  be  concentrated  on  the  sand- 
bath  in  a  shallow  vessel,  the  solution  solidifies  to  a  compact  mass  of 
crystals,  consisting  of  the  dichlorhydrate  of  hydrochlorapocinchonidia,, 
while  the  apocinchonidia  remains  dissolved  in  the  mother-liquid.  As 
this  mass,  however,  is  very  slippery,  and  by  pressing  passes  for  the 
most  part  through  the  press-cloths,  etc.,  a  great  loss  of  material  would 
be  sustained  and  only  a  small  amount  of  pure  dichlorhydrate  be 
obtained.  The  following  method  gives  good  results  :  The  mixture  in 
question  is  dissolved  in  dilute  sulphuric  acid,  to  the  hot  solution  an 
equal  volume  of  alcohol  is  added,  and  alcoholic  ammonia  by  drops 
until  litmus  paper  is  only  slightly  reddened ;  the  alcohol  is  then 
evaporated,  when  the  hydrochlorapocinchonidia  will  separate,  and  ^nay 
be  purified  by  recrystallization  from  boiling  alcohol. 
This  separation  is  founded  upon  the  fact  that  apocinchonidia  neu- 
tralizes sulphuric  acid,  while  the  other  base  does  not  possess  this  pro- 
perty. Another  process  of  separation  is  based  upon  the  hydrochlor- 
apocinchonidia sulphate  crystallizing  well  from  water,  while  the  apo- 
cinchonidia sulphate  is  amorphous  and  freely  soluble. 
The  hydroclilorapocinchonidia  obtained  from  boiling  alcohol  is  in 
colorless  scales  of  a  silky  lustre,  difficultly  soluble  in  ether,  chloroform^, 
cold  and  hot  alcohol,  and  melting  at  200°C.  (uncorr.)  It  is  Isevogy- 
rate ;  the  deviation  of  the  alcoholic  solution,  on  account  of  the  slight 
concentration,  could  not  be  observed  with  the  proper  precision ;  in. 
water  with  3HC1  it  is — 142*2°.  The  hydrochloric  acid  solution  gives^ 
