PRESENT  STATE  OF  OUR  KNOWLEDGE  OF  CINCHONA.  417 
OBSERVATIONS  ON  THE  PRESENT  STATE  OF  OUR  KNOW- 
LEDGE OF  THE  GENUS  CINCHONA. 
By  John  Eliot  Howard,  F.L.S. 
(Abstract  of  a  Paper  read  at  a  Meeting  of  the  International  Botanical  Congress,  and  prepared  by 
the  Author,  by  deBire,  for  the  Pharmaceutical  Journal.) 
The  writer  approaches  the  consideration  of  the  Cinchonaceous 
plants  rather  more  from  a  practical  than  from  a  technically  bo- 
tanical point  of  view,  and  thinks  that  much  remains  yet  to  be 
done  by  careful  study  of  the  plants  themselves,  to  reduce  Botani- 
cal terms  to  harmony  with  Pharmaceutic  requisitions,  and  thus 
to  discriminate  between  forms  which,  in  a  therapeutic  point  of 
view,  produce  wholly  different  products,  and  which  have  been 
thrown  together  by  systematic  arrangement  founded  on  in- 
sufficient data.  The  C.  micrantha  of  Huanuco,  for  instance, 
produces  a  "grey  bark,"  characterized  by  its  abundant  yield  of 
pure  cinchonine  ;  whilst  the  0.  micrantha  of  Bolivia  differs  widely 
in  its  chemical  contents,  and  presents  apparently  a  somewhat 
differing  form.  Again,  the  0.  ovata  of  Pavon  and  of  Peru,  gives 
an  entirely  worthless  bark  producing  aricine  (or  paracin),  whilst 
the  0.  ovata,  var.  rufinervis,  Wedd.,  of  Bolivia,  is  a  plant  allied 
to  the  Calisaya  in  its  products,  and  the  C.  ovata,  var.  erythro- 
derma, approaches  to,  and  is  not  improbably  found  amongst  the 
red-bark-producing  plants. 
Mr.  Howard  does  not  propose  to  found  a  diagnosis  of  species, 
either  on  the  chemical  constituents  of  the  barks,  or  on  their 
microscopical  constitution,  but  to  follow  out  more  fully,  and  to  a 
greater  extent,  the  consideration  of  the  barks  as  assisting  in  the 
discrimination  of  species  and  varieties,  according  to  the  precedent 
so  ably  established  by  Dr.  Weddell  in  his  admirable  "  Histoire 
des  Quinquinas." 
Mr.  Howard  is  nearly  in  accordance  with  Dr.  Weddell  and 
with  M.  Gustave  Planchon  (whose  recently  published  work*  he 
regards  as  the  most  valuable  manual  that  has  yet  appeared  on 
the  subject),  in  regarding  "  Cinchona  as  forming  a  very  natural 
genus,  the  different  forms  of  which  often  pass  from  one  into 
another  by  insensible  transitions,"  but  leaving  it  open  for  fur- 
*  "Des  Quinquinas,"  par  Gustave  Planchon  ;  Savy,  Paris,  1864. 
27 
