^vemie^mS'}    The  Apocynacecz  in  Materia  Medica.  543 
fragile,  of  which  the  inferior  part  is  naked  and  the  upper  adorned 
with  long  hairs,  fine  and  delicate. 
The  hairs  of  the  seed  and  of  the  awn  are  alike,  excepting  the 
length  of  the  latter,  unicellular,  and  with  one  long  canal  running 
through,  ordinarily  filled  with  air.  Those  of  the  surface  slightly 
enlarged  at  the  base. 
The  anatomical  structure  of  the  sled  is  fully  described  under  each 
species.  It  is  especially  important  to  be  well  acquainted  with  the 
external  tegument,  because  the  thickening  of  the  lateral  walls  of  the 
cells  vary  in  form  and  characterize  the  species.  The  second  tegu- 
ment with  a  larger  number  of  layers  of  cells,  but  ordinarily  very 
flattened,  brown  and  difficult  to  distinguish,  is  likewise  important. 
Beneath  these  is  the  albumen,  relatively  greatly  reduced  and  enclos- 
ing the  embryo.  The  albumen  consists  of  cells  with  rather  thick 
walls  and  contains  the  oil.  The  embryo  is  formed  of  slender  cells, 
between  the  two  epiderms  of  the  cotyledons.  It  contains  numerous 
droplets  of  oil  and  sometimes  crystals  of  calcium  oxalate  in  macles. 
Between  the  albumen  and  the  embryo  is  a  sort  of  loose  tissue,  pointed 
out  by  Blondel.  Finally,  numerous  laticiferous  vessels  are  near  the 
cotyledonary  fascicles  and  even  in  the  seminal  tegument.  Starch 
is  very  rarely  abundant  and  often  absent.  The  embryo  and  the 
albumen  contain  especially  the  active  principle. 
It  is  generally  said  that  the  seeds  of  Strophanthus  are  inodorous; 
they  are  very  little  odorous  in  the  ordinary  condition,  but  if  crushed 
they  exhale  a  peculiar  odor,  slightly  poisonous,  and  on  contusing  in 
a  mortar,  one  feels  quite  an  irritation  of  the  mucous  membranes.  The 
taste  is  atrociously  bitter  in  the  best  sorts. 
The  researches  of  Fraser,  Hanauseck,  Helbing  and  Hartwich  on 
the  mxrochemical  characters,  permit  the  recognition  of  the  presence 
of  strophanthine  in  the  seed,  and  consequently,  to  estimate  rapidly 
their  value.  The  reaction  the  most  interesting  is  that  given  by  con- 
centrated sulphuric  acid.  Helbing  proposed  to  moisten  the  section 
with  a  trace  of  solution  of  ferric  chloride,  then  to  add  one  drop  of 
the  acid.  Sulphuric  acid  in  contact  with  a  trace  of  Strophanthine 
gives  with  this  a  green  coloration,  which,  according  to  Fraser, 
changes  in  five  minutes  to  a  greenish  yellow  and  finally  gradually 
turns  to  a  brownish  green  from  the  centre  to  the  periphery  in  twenty 
minutes,  or  from  a  greenish  gray  to  a  dirty  brown  in  one  or  two 
hours.  Hanauseck  described  the  color  reactions  of  the  various  parts 
