Am.  Jour.  Pharm. 
June,  1897. 
Alexandria  and  India  Senna. 
305 
dermis,  would  be  more  accurate  than  counting  the  free  hairs  in  the 
powder ;  but  it  is  really  unreliable,  because  the  distribution  of  the 
hairs  is  not  uniform.   This  objection  does  not  apply  to  the  counting 
Fig.  6.  Alexandria  senna,  No.  60  powder  ;  b,  stomata  ;  c,  hairs  ;  d,  hair 
scars  ;  e,  nebenzellen. 
of  the  free  hairs,  for  by  powdering  the  leaves  and  shaking  the  pow- 
der up  in  a  liquid,  the  distribution  is  made  comparatively  uniform. 
