ON  THE  ALKALOIDS  OF  THE  CINCHONAS. 
535 
a  low  temperature  ;  and  it  is  sufficient  to  keep  it  in  this  state  at  a 
temperature  of  248°-266°  F.  for  three  or  four  hours,  to  convert  it 
entirely  into  sulphate  of  cinchonicine.  The  production  of  coloring 
matter  is  very  trifling,  nearly  inappreciable. 
I  prove,  by  facts  which  will  be  accepted  by  all  chemists,  that 
if  heat  plays  a  great  part  in  this  transformation  of  cinchonine, 
the  vitreous,  resinoid  state  of  the  product  has  a  certain  influence  ; 
and  the  present  case  of  isomerism  certainly  related  to  those  meta- 
morphoses, of  which  mineral  chemistry  offers  us  several  examples, 
such  as  soft  sulphur,  red  phosphorus,  and  vitreous  arsenious  acid. 
2.  Qwinicine. — All  that  has  been  stated  in  the  preceding  section 
with  regard  to  cinchonine  applies  equally  to  quinine.  Any  salt 
of  this  base,  heated  in  the  same  manner  as  the  salt  of  cinchonine, 
is  also  converted  into  a  new  base  isomeric  with  quinine.  I  call 
this  new  base  quinicine.  The  most  convenient  mode  of  preparing 
it  consists  in  adding  a  little  water  and  sulphuric  acid  to  the  sul- 
phate of  quinine  of  commerce,  and  exposing  it  to  the  heat  of  an 
oil-bath  of  248°— 266°  F.  for  three  or  four  hours;  the  salt  remains 
fused  even  after  the  expulsion  of  all  the  water,  and  becomes  com- 
pletely converted  into  sulphate  of  quinicine,  with  a  very  minute 
production  of  coloring  matter. 
As  regards  the  general  properties  of  cinchonicine  and  quinicine, 
they  offer  well-marked  analogies  with  the  isomeric  bases  from 
which  they  are  derived.  They  especially  present  the  greatest  re- 
semblance to  one  another.  Both  of  them  are  nearly  insoluble  in 
water,  but  very  soluble  both  in  absolute  and  ordinary  alcohol. 
They  both  combine  readily  with  carbonic  acid,  and  expel  ammonia 
from  its  saline  combinations  in  the  cold.  They  are  both  pre- 
cipitated from  their  solutions  in  the  form  of  fluid  resins  in  the 
same  manner  as  quinine  under  certain  circumstances.  They  both 
deviate  the  plane  of  polarization  to  the  right.  They  are  very 
bitter  and  febrifuge. 
3.  Quinidine. — The  contradictions  to  be  met  in  the  works  of 
chemists  with  regard  to  this  substance  all  arise  from  a  fact  which 
has  escaped  them,  namely,  that  under  the  name  of  quinidine  two 
very  distinct  alkaloids  have  been  confounded  ;  these  are  nearly 
constantly  associated  by  mixture  in  commercial  quinidine,  if  it  has 
not  been  purified  by  several  successive  crystallizations.  Thus  the 
quinidine  discovered  in  1833  by  Henry  and  Delondre  is  quite  a 
