Am"sep£  Sarm' }     Quinine,  Cinckoitidine  and  Isomers.  45 1 
Hence  it  follows  that  the  existence  of  homocinchonidine  was  not 
placed  in  doubt,  as  de  Vrij  has  supposed,  by  the  paper  of  Skraupand 
Vortmann,  but  on  the  contrary  it  was  proved,  and  it  was  really  the 
existence  of  the  base  to  which  Dr.  Hesse  gave  the  name  of  cin- 
chonidine  that  was  disputed.  Subsequently,  indeed,  Skraup 
endeavored  to  prove  the  non-existence  of  this  latter  base  by  means 
of  preparations  obtained  from  Dr.  Hesse.  In  regard  to  that  attempt 
it  is  a  sufficient  justification  of  Dr.  Hesse's  view  that  two  years  ago 
de  Vrij  unintentionally  supported  the  existence  of  the  base  which  Dr. 
Hesse  had  named  cinchonidine  by  making  -known  a  simple  method 
of  preparing  it. 
In  reference  to  this  communication  of  de  Vrij's,  Dr.  Hesse  men- 
tions that  he  had  from  time  to  time  prepared  the  tetrasulphate 
originally  described  by  him,  recrystallizing  it  from  dilute  sulphuric 
acid  or  from  alcohol,  then  neutralizing  the  water  solution,  and 
separating  from  the  sulphate  deposited  the  still  adhering  homocin- 
chonidine by  means  of  recrystallization  from  water  in  the  manner 
that  has  been  described.  A  pure  cinchonidine  salt  may  be  obtained 
even  by  repeated  recrystallization  of  the  tetrasulphate  from  dilute 
sulphuric  acid  or  alcohol,  as  shown  by  Dr.  Hesse  more  than  ten 
years  ago,  so  that  this  fact  was  already  known  in  1887  when  de 
Vrij  supposed  it  had  been  discovered  by  Schafer.  The  uncorrected 
melting  point  of  cinchonidine  was  found,  as  previously  stated  by  Dr. 
Hesse,  to  be  from  19970  to  200*5°C.  (mean  about  200- 1 0  C),  when 
determined  by  the  method  then  in  use  (Clauss  gives  2010  C,  Schafer 
1990),  and  that  of  homocinchonidine  was  found  to  be  from  2050  C. 
to  2060  C,  or  nearly  six  degrees  higher  than  the  melting  point  of 
cinchonidine.  By  the  use  of  Roth's  apparatus  the  melting  point  of 
cinchonidine  was*found  to  be  from  2020  C.  to  202-8°  C,  mean  202-4° 
C,  and  that  of  homocinchonidine  from  207°  to  208-2°  C,  mean 
207-6°.  By  the  same  means,  Lenz,  without  attempting  a  separation 
of  homocinchonidine  from  cinchonidine,  found  the  melting  point  of 
the  base  obtained  from  once  recrystallized  tetrasulphate  to  be  from 
2070  C.  to  207-5°  C,  that  of  twice  recrystallized  salt  204-5°  t0 
205°  C.,and  that  of  the  base  crystallized  from  ether  205°  C.  to  206° 
C,  while  that  of  a  sample  of  cinchonidine  obtained  from  Dr.  Hesse 
was  found  to  be  204-5°  C.  to  205-2°  C,  or  in  all  instances  higher 
than  that  of  cinchonidine.  Whether  these  differences  were  due  to 
the  presence  of  some  homocinchonidine  or  to  other  circumstances  it 
