Amjuiy?if93arm-}      Strophanthus  Seed  of  Commerce.  345 
satisfactory  method  of  applying  the  test  is  to  cut  a  thin  transverse 
section  of  the  seed  with  a  razor,  place  it  on  a  glass  slide  and  add  a 
drop  of  concentrated  sulphuric  acid.  If  the  seed  contains  stro- 
phanthin,  the  endosperm  or  embryo  or  both  will  exhibit  a  dark 
green  coloration,  after  the  lapse  of  a  minute  or  more,  according  to 
the  species  operated  on.  In  seeds  containing  no  strophanthin,  a  red 
color,  of  different  intensity  or  shade  in  different  species,  is  slowly 
developed. 
To  ascertain  the  presence  of  strophanthin  in  an  extract  or  tinc- 
ture of  the  seed,  a  piece  of  the  former,  about  twice  the  size  of  a 
pin's  head,  or  three  drops  of  the  latter,  may  be  mixed  with  half  a 
drop  of  solution  of  perchloride  of  iron  and  three  drops  of  concen- 
trated sulphuric  acid.  A  brown  precipitate  is  formed  which  becomes 
green  in  an  hour,  the  color  persisting  for  three  hours. 
A  feature  which  may  be  employed  to  distinguish  seeds  of  the 
genus  Strophanthus  from  those  of  allied  genera  has  been  pointed 
out  by  Herr  Hartwich.  In  the  epidermal  cells  of  the  seeds  a  ring- 
like or  annular  thickening  is  found,  which  is  absent  in  the  seeds  of 
any  other  apocynaceous  genus  with  which  Strophanthus  seeds  could 
possibly  be  confounded.  In  the  seeds  of  Strophanthus  glaber,  Max 
Cornu,  M.S.,  and  in  Kickxia  Africana,  however,  a  different  thicken- 
ing, in  the  form  of  linear  bands  (balkenf  brmige)  has  been  observed. 
For  convenience  of  comparison,  the  seeds  examined  by  Herr 
Hartwich  may  be  grouped  as  follows  : 
I.  Hairy  brown  seeds  of  the  5.  hispidus  type. 
II.  Hairy  grayish  green  seeds  of  the  S.  Kombe  type. 
III.  Hairy  whitish  seeds  with  a  dense  coat  of  long  hairs. 
IV.  Glabrous  seeds.    (See  Table  A.) 
I  have  compared  all  the  specimens  existing  in  the  Museum  of  the 
Pharmaceutical  Society  so  far  as  regards  size  and  chemical  reaction, 
with  the  results  recorded  in  the  table.    (See  Table  B.) 
On  comparing  these  tables  it  will  be  observed  that,  if  the  geo- 
graphical sources  can  be  depended  on,  there  are  brown  seeds  con- 
taining no  strophanthin  which  come  from  the  same  countries  as 
other  brown  seeds  in  which  strophanthin  can  be  detected,  and  that 
the  same  remark  applies  to  the  grayish  green  seeds.  Even  in  a 
specimen  received  from  Professor  Fraser,  as  the  seed  with  which  his 
recent  experiments  had  been  made,  two  kinds  of  seed  (Nos.  9  and 
10)  were  present. 
