THE  AMERICAN 
JOURNAL  OF  PHARMACY 
NOVEMBER,  1896. 
SENNA. 
TO  DISTINGUISH  BETWEEN  THE  ALEXANDRIA  AND  INDIA  VARIETIES  IN 
POWDER,  AND  TO  EXCLUDE  POWDERED  CHESTNUT  LEAVES. 
By  L.  K.  Sayrk, 
Member  of  the  Research  Committee,  of  the  Committee  of  Revision  of  the 
United  States  Pharmacopoeia. 
One  of  the  problems  presented  to  the  members  of  the  Research 
Committee  is  expressed  by  the  title  to  this  paper.  The  writer  will 
endeavor  to  answer  it  as  briefly  as  possible. 
The  two  sennas,  Alexandrian  and  Indian,  in  the  powdered  state, 
have  many  points  of  resemblance  and  few  of  diversity.  In  the 
whole  state  it  is  well  known  that  a  discrimination  is  readily  made 
without  the  use  of  a  lens  or  reagent.  In  the  powdered  state  the 
task  becomes  more  difficult.  There  are  two  points  of  difference 
that  even  a  moderately  acute  observer  will  notice : 
(1)  The  small  number  of  plant  hairs  in  one  case  and  the  much 
greater  number  in  the  other. 
(2)  In  the  dissimilarity  of  form  of  the  epidermal  cells.  Both  of 
these  points  of  distinction  will  be  referred  to  more  at  length. 
(1)  If  equal  amounts  of  the  Alexandrian  and  Indian  varieties  in 
No.  60  powder  be  taken,  it  will  be  seen  that  there  are  about  ten 
plant  hairs  of  the  former  to  one  of  the  latter  variety.  If  25  milli- 
grammes of  the  powdered  sennas  under  examination  be  mixed  with 
5  c.c.  of  diluted  alcohol,  and  one  drop  of  the  mixture  be  examined 
under  the  microscope,  there  will  be  found  in  the  India  senna  from 
one  to  three  of  the  plant  hairs,  and  in  the  Alexandria  variety  from 
(585) 
