MICROSCOPICAL  RESEARCHES  ON  THE  ALKALOIDS.  347 
the  existence,  as  visible  under  the  microscope,  of  the  Cinchona 
alkaloids,  in  situ,  in  the  bark.  I  am  far  from  supposing  that 
any  such  practical  application  can  be  made  of  this  discovery, 
which  I  announced  in  my  "  Nueva  Quinologia  "  in  the  year  1861, 
for  the  following  reason  : — the  combinations  of  the  alkaloids  with 
kinic  acid  are  extremely  soluble,  so  that  in  any  bark  in  which 
these  are  the  prevalent  constituents,  it  is  very  difficult  to  ascertain 
any  crystalline  appearance.  But  this  is  not  the  case  in  all  cin- 
chona barks,  as  for  instance  in  the  commercial  red  bark,  the  O. 
succirubra,  in  which  the  prevalent  combination  appears  to  be  of 
a  different  kind.  It  is  in  reference  to  a  very  fine  specimen  of 
this  red  bark  that  I  published  the  following  observations : 
"  In  order  to  gain  as  much  information  as  possible  from  the 
rich  bark  under  consideration,  I  made  sections  of  a  portion  for 
microscopic  investigation,  and  was  rewarded  by  some  appearances 
which  I  had  not  before  seen.  The  eye  was  at  once  arrested  by 
very  numerous  stellate  groups  of  crystals,  diffused  irregularly 
throughout  the  substance  of  the  bark.  I  thought  at  first  that 
they  must  be  raphides  ;  but  further  investigation  led  me  to  see 
that  they  are  entirely  soluble  in  spirit  of  wine,  and  even  in  ether, 
that  they  polarize  the  ray  of  light,  and  thus  much  more  resemble 
combinations  of  the  alkaloids  than  those  bodies  which  are  called 
raphides,  and  which  are  understood  to  be  composed  of  salts  of 
lime  and  magnesia,  insoluble  in  the  media  above  named. 
"  The  crystals  are  arranged  in  the  substance  of  the  bark  in- 
determinately, and  without  any  reference  to  the  organic  structure 
of  the  bark.  They  are  not  formed  in  the  cells,  but  cross  these 
in  every  direction, — radiating  generally  from  some  small  nu- 
cleus, and  presenting  very  much  the  appearance  of  some  com- 
pounds of  the  alkaloids  in  their  crystalline  form.  They  evidently 
are  not  the  product  of  vital  processes  taking  place  in  the  plant 
in  its  living  state,  but  must  result  from  changes  in  the  juices  of 
the  bark  after  its  removal  from  the  tree  ;*  indeed,  it  can  be  no 
*  "Seven  pounds  of  green  give  four  pounds  of  dry  bark  in  this  species; 
(<7.  succirubra),  (Spruce,  Report,  etc.,  p.  28,)  while  the  freshly-peeled  bark 
of  the  C.  lancifolia  dries  to  one-third  of  its  weight  (Karsten,  Medicinische 
Chinarinden,  etc.,  p.  17),  so  much  greater,  in  its  growing  state,  is  the 
density  of  the  fluid  constituents  in  the  former  kind  of  bark  than  in  the 
latter." 
