ON  THE  ALKALOIDS  OF  THE  CINCHONAS. 
537 
of  chemists,  take  a  new  character  when  we  compare  the  rotatory 
powers  of  the  six  preceding  alkalies.  Quinine  deviates  to  the 
right,  quinidine  to  the  left — both  to  a  considerable  extent.  Quini- 
cine  deviates  to  the  right,  but  to  a  very  small  extent  compared 
with  the  rotatory  powers  of  the  two  others.  The  same  relations 
are  presented  by  the  three  other  isomeric  bodies,  cinchonine,  cin- 
chonidine,  and  cinchonicine.  Cinchonine  deviates  to  the  right, 
cinchonidine  to  the  left,  both  considerably  ;  cinchonicine,  on  the 
contrary,  produces  very  slight  deviation  to  the  right.  The  most 
logical  interpretation  of  these  results  is  the  following  : — The 
molecule  of  quinine  is  double,  formed  of  two  active  bodies,  one 
which  deviates  considerably  to  the  left,  and  the  other  very  slightly 
to  the  right.  The  latter,  which  is  permanent  under  the  influence 
of  heat,  resists  isomeric  transformation,  and  remaining  without 
alteration  in  the  quinicine,  gives  this  its  feeble  deviation  to  the 
right.  The  other  group,  which  on  the  contrary  is  very  active, 
becomes  inactive  when  the  quinine  is  heated  so  as  to  become  con- 
verted into  quinicine  ;  so  that  quinicine  is  nothing  but  quinine  in 
which  one  of  the  active  constituent  groups  has  become  inactive. 
Quinicine  would  also  be  quinidine  in  which  one  of  the  active  con- 
stituent groups  had  become  inactive;  but  in  quinidine  this  very 
active  group  would  be  right  instead  of  left  as  in  quinine,  but  still 
united  with  the  same  slightly  active  right  group,  which  being  per- 
manent remains  in  the  quinicine,  and  gives  it  its  weak  right 
deviation.  I  might  repeat  all  that  I  have  said  word  for  word,  ap- 
plying it  to  cinchonine,  cinchonidine  and  cinchonicine,  which  are 
respectively  constituted  like  their  three  congeners  ;  they  offer  ex- 
actly the  same  relations. 
5.  Quinoidine. — I  shall  not  enter  into  the  detail  of  the  experi- 
ments which  I  have  undertaken  upon  quinoidine  ;  but  there  is  one 
point  to  which  I  wish  to  call  the  attention  of  manufacturers  of 
sulphate  of  quinine  and  of  the  companies  who  collect  the  barks  of 
cinchonas  in  America.  Quinoidine  is  always  a  product  of  the 
alteration  of  the  alkalies  of  the  cinchonas.  It  has  two  distinct 
origins.  It  is  produced  in  the  operations  for  the  manufacture  of 
sulphate  of  quinine,  and  especially  in  the  forests  of  the  New  World, 
when  the  wood-cutter,  after  stripping  the  bark  from  the  tree,  ex- 
poses it  to  the  sun  to  dry  it.  Then  the  salts  of  quinine,  cinchonine, 
&c.  contained  in  the  bark,  become  converted  into  resinous  and 
