PRESENT  STATE  OF  OUR  KNOWLEDGE  OF  CINCHONA.  419 
another  department  of  science,  taking  as  an  instance  the  names 
of  the  alkaloids  produced  by  these  same  plants,  which,  according 
to  the  first  impressions,  ranged  thus  : — 
Quinine.  Cinchonine. 
Quinidine.  Cinchonidine. 
Quinicine.  Cinchonicine. 
Further  and  more  careful  examination  shows  a  different  arrange- 
ment, as  indicated  by  their  properties  in  reference  to  the  ray  of 
plane  polarized  light. 
Quinine.  Cinchonine.  Cinchonicine. 
Cinchonidine.       Quinidine.  Quinicine. 
Powerfully  laevogyrate.  Preeminently  dextrogyrate.  Feebly  dextrogyrate. 
This  latter  being  the  true  relation,  as  shown  by  Dr.  Herapath 
m  his  communications  to  the  Royal  Society,  on  chemical  grounds, 
and  by  Mr.  Howard  in  Reports  to  the  Under-Secretary  of  State 
for  India,  on  specimens  of  bark  grown  in  that  country,  from 
which  it  appears  that  it  is  the  order  in  which  in  the  plants  them- 
selves these  alkaloids  are  produced,  normally  in  concert,  and 
under  circumstances  of  changed  locality  are  supplemented,  or 
even  superseded  by  each  other.  Thus  the  quinine-producing 
Calisaya  forms  always  some,  and  abnormally  much  cinchonidine, 
and  the  cinchonine-producing  C.  micrantha  of  Peru  forms  in 
India  a  large  product  of  quinidine. 
Mr.  Howard  thinks  the  species  of  Calisaya  can  be  best 
studied  in  connection  with  the  different  geographical  centres, 
the  products  of  which  he  proposes  briefly  to  review,  so  far  at 
least  as  concerns  their  most  prominent  species,  beginning  with 
Bolivia. 
The  Barks  of  Bolivia. 
Cinchona  Calisaya,  Weddell. — This  species  certainly  merits 
the  first  mention.  It  is  beyond  all  question  the  first  in  import- 
ance in  commerce,  as  furnishing  the  bark  most  largely  used  in 
the  production  of  the  precious  medicine  quinine.  It  contains 
this  product  in  remarkable  purity,  with  very  little  admixture  of 
any  other  alkaloid — a  fractional  quantity  of  cinchonidine  and 
cinchonine  being  (in  the  best  specimens)  the  only  exception. 
It  is  not  to  be  supposed  that  the  products  of  wild  forests 
