586 
"Semta. 
(Am.  Jour.  Pharm. 
I  November,  1898. 
eight  or  ten  to  twenty  or  more;  the  number  in  both  cases  varies  of 
course. 
On  very  close  observation  it  will  also  be  seen  that  the  plant  hairs 
in  the  Alexandrian  senna  have  a  sharp  curve  near  the  base,  indica- 
ting that  they  are  more  or  less  appressed  on  the  leaf,  while  in  the 
Indian  variety  the  hairs  are  shorter,  straighter  and  stouter.  The 
plant  hairs  almost  invariably  remain  unbroken  in  the  powder. 
Hence,  from  this  we  may  reasonably  expect  an  admixture  of  the 
two  varieties  in  the  powdered  state  to  produce  an  effect  recognizable 
Fig.  i. — Alexandrian  senna,  about  260  diameters,  a,  ordinary  epidermal 
cell ;  n,  stoma  ;  h,  plant  hairs  ;  hn,  broken  fragment ;  s,  scars. 
to  any  one  familiar  with  the  appearance  of  these  varieties  under 
the  microscope. 
(2)  Epidermal  cells.  The  cell  structure  represented  by  the  epi- 
dermal tissue  seems  also  to  be  a  recognizable  one  in  the  fine  powder. 
In  the  Indian  senna  the  epidermal  cells  are  somewhat  smaller  and 
more  uniform  in  size,  and  the  angles  more  acute  than  in  the  Alexan- 
drian variety.  The  second  difference — epidermal  cells — is  not  one 
that  could  be  successfully  employed,  except  by  experts,  perhaps,  in 
distinguishing  the  powdered  sennas  ordinarily,  or  in  detecting  mix- 
tures of  the  two. 
