^March.S!'111"}    The  Apocynacece  in  Materia  Medica.  16$ 
Conessi  Bark. — Conessi  Bark  or  Tellichery  is  obtained  from 
Holarrhena  antidysenterica  R.Br.  In  its  native  country  it  has  a 
great  reputation  and  is  known  there  under  the  name  of  Codaga-pala. 
The  true  Holarrhena  bark  is  in  curved  pieces  of  varying  size.  Ex- 
ternally it  is  earthy  brown  to  a  light  fawn  color,  irregularly  striated 
with  oblique  furrows.  Internally,  the  striations  are  always  longi- 
tudinal. 
The  fracture  shows  an  external  rose-colored  zone,  an  internal  zone 
with  brownish  striations.  The  bark  is  quite  thick.  As  previously 
stated  it  is  frequently  substituted  by  products  from  various  species 
of  Wrightia,  and  to  this  is  attributed  the  unsatisfactory  results 
obtained  in  Europe.  It  is  largely  used  in  India  as  a  remedy  in  dys- 
entery. The  bark  contains  the  same  alkaloid  as  the  seeds, 
Wrightine. 
DITA  BARK. 
Dita  or  Alstonia  bark  is  obtained  from  Alstonia1  scholaris2  R.Br., 
which  tree  is  very  common  in  the  forests  of  India.  The  remedy 
was  introduced  into  Europe  by  Graham,  in  1839,  and  Alexander 
Gibson,  in  1853,  contributed  an  account  of  the  drug.  The  bark  as 
it  enters  commerce  is  in  more  or  less  contorted  fragments  of  vary- 
ing size,  and  in  thickness  from  4  to  12  m.m.  The  external  face  is 
frequently  marked  with  blackish  lichens  and  in  some  fragments  the 
suberous  portion  is  quite  thick;  the  periderm  is  reddish-brown. 
Frequently  it  is  marked  by  large  transverse  lines  and  fissures  and 
leaf-scars.  The  internal  face  shows  a  tough  grey  or  brownish-grey 
zone.  The  fracture  is  short,  granular,  porous  but  not  fibrous  and 
yellowish-white.  The  microscopic  structure  shows  the  suber,  (where 
it  remains),  formed  of  cells  very  regularly  piled  up  in  series  some- 
what tangentially  elongated  and  at  times  with  a  reddish-brown  con- 
tents. Immediately  beneath  the  suber  is  a  layer  of  small  cells, 
nearly  all  of  which  contain  a  large  rhombohedral  crystal  of  oxalate. 
1The  genus  Alstonia  was  named  in  honor  of  Charles  Alston,  a  professor  of 
botany,  at  Edinburgh,  about  the  middle  of  the  last  century.  It  consists  of 
large  trees  with  verticillate  or  opposite  leaves,  calyx  without  appendages, 
corolla  without  crown,  stamens  included,  two  carpels  containing  numerous 
ovules,  two  follicles  elongated  and  seeds  peltate  and  are  rich  in  caoutchouc. 
2  The  specific  name  scholaris  was  applied  to  this  plant,  because  in  the  schools 
of  India  school-boards  are  constructed  from  planks  of  this  tree,  the  fine 
grained  wood  being  well  adapted  for  such  purposes. 
