Amsfcf7n7T'}      The  Alkaloids  of  Cinchona  Trees.  465 
The  constitution  of  the  alkaloids  of  the  renewed  bark  affords  curious 
points,  both  of  resemblance  and  contrast  to  that  of  the  root.  There 
is  seen  in  the  renewed  bark  also  an  increased  yield  of  alkaloids,  but  in 
this  case  the  increase  of  the  more  oxidized  alkaloids,  quinia  and 
its  isomers,  is  accompanied  by  a  distinct  diminution  of  cinchonia  and 
cinchonidia. 
This  is  most  evident  in  the  C.  succirubra,  the  proportion  of  quinia 
and  cinchonidia  being  inverted  by  the  process,  while  the  slight  diminu- 
tion of  the  cinchonia  is  accompanied  by  an  increase  of  the  quinidia 
from  '03  per  cent,  to  '14  per  cent.,  but  the  same  change  takes  place  in 
the  bark  of  the  C.  officinalis,  where  the  cinchonidia  almost  disappears, 
and  the  quinidia  is  markedly  increased  in  quantity,  the  amorphous  alka- 
loids being  in  each  species  increased  by  the  process. 
The  renewing  of  the  bark  has  only  been  carried  on  as  yet  on  the 
Neilgherries,  but  it  is  to  be  hoped  that  the  great  commercial  success 
which  has  attended  the  experiment  will  lead  to  its  adoption,  if  practi- 
cable, elsewhere,  when  we  shall  see  if  the  modification  of  the  alkaloid 
follows  the  same  rule  under  all  circumstances. 
The  variations  shown  by  C.  succirubra,  under  the  influence  of  climate 
and  soil,  are  also  very  interesting.  This  species  of  cinchona  alone 
seems  to  be  sufficiently  hardy  to  adapt  itself  to  varied  circumstances, 
growing  alike  at  Darjeeling  where  the  other  species  have  proved  almost 
total  failures,  in  the  Neilgherries  where  the  climate  seems  the  best 
suited  for  the  C.  officinalis,  and  in  Java  in  the  habitat  so  singularly 
favorable  to  the  C.  Ledgeriana. 
The  proportion  of  the  alkaloids  varies,  however,  very  distinctly  under 
these  varied  circumstances.  Except  under  the  artificial  treatment  of 
renewing  the  bark,  it  is  never  rich  in  quinia,  but  the  cinchonidia  and 
cinchonia  show  very  interesting  variations. 
In  Java  the  cinchonidia  predominates  in  a  most  marked  degree. 
On  the  Neilgherries,  though  cinchonidia  is  still  predominant,  cincho- 
nia shows  an  increase.  On  the  Himalayas  the  bark  shows  a  dimin- 
ished yield  of  cinchonidia,  but  a  marked  increase  of  cinchonia  and 
amorphous  alkaloid. 
Not  having  been  able  to  get  particulars  of  the  various  elevations  at 
which  bark  is  grown  in  Ceylon,  I  cannot  speak  with  certainty  as  to  the 
different  specimens  obtained  from  that  island,  but  as  far  as  I  can  judge, 
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