366 
Digitalis  Hairs. 
(  Am.  Jour.  Pharm. 
I      AugU6t,  1911. 
this  is  the  practice  of  many  discriminating  pharmacists  in  the 
United  States. 
Of  all  the  papers  which  have  been  published  on  digitalis,  the 
one  by  Hartwich  and  Bohny  ^  seems  to  me  to  be  the  most  impor- 
tant from  a  pharmacognostical  standpoint.  The  whole  work  is  of 
a  basic  character  and  sets  forth  many  observations  showing  varia- 
tion in  the  structure  of  wild  plants  and  those  selected  from  culti- 
vated varieties.  These  authors  point  out  that  among  other  things 
that  the  leaves  of  wild  digitalis  are  usually  more  hairy,  that  the 
cells  of  the  hairs  are  shorter  and  broader  and  that  the  cuticle,  or 
outer  walls,  of  the  middle  and  lower  cells  of  the  non-glandular  hairs 
are  finely  papillose.  Vogl  -  has  called  attention  to  the  fact  that 
the  end  cells  are  occasionally  either  fine  striated  or  slightly  papillose. 
As  a  matter  of  fact  the  observations  of  both  of  these  authors  are 
correct.  In  regard  to  the  number  of  cells  making  up  these  non- 
glandular  hairs,  Vogl  states  that  they  are  mostly  3-celled,  Hart- 
wich and  Bohny  state  that  they  are  usually  2-  to  4-celled  and  seldom 
5-  to  6-celled,  and  Greenish  ^  records  the  fact  that  exceptionally 
they  may  be  as  many  as  ten  cells  long.  While  I  have  not  been  able 
to  confirm  Greenish's  observation,  I  have  seen  specimens  in  which 
many  of  the  hairs  were  7  to  8  cells  long,  and  I  believe  that  his 
statement  can  be  confirmed.  Most  authors  agree  that  the  head 
or  glandular  portion  of  the  glandular  hair  consists  oi  one  or 
two  cells  but  Hartwich  and  Bohny  state  that  they  are  seldom  i- 
or  4-celled.  The  stalks  of  these  glandular  hairs  are  usually  i-  or 
2-celled.  A  most  interesting  observation  is  recorded  by  Hartwich 
and  Bohny  that  in  between  the  veins  occur  long  glandular  hairs 
with  usually  a  4-celled  stalk  and  a  i -celled  glandular  head.  These 
observations  are  all  of  the  very  greatest  interest  and  should  be 
borne  in  mind  by  students  and  practical  workers  in  pharmacognosy. 
The  entire  leaf  of  digitalis  is  very  characteristic,  being  more 
or  less  elliptical  and  the  lower  portion  extending  into  the  petiole 
(Fig.  i).  The  margin  is  irregularly  crenate  but  the  most  char- 
acteristic feature  is  the  venation.  From  the  central  vein  extend  a 
number  of  prominent  veins  of  the  first  order  that  diverge  at  angles 
of  twenty  to  forty-five  degrees,  which  serves  to  distinguish  it 
from  inula,  in  which  the  angles  between  the  primary  veins  and 
the  mid-rib  are  from  sixty-five  to  nearly  eighty  degrees.  The  vena- 
tion at  the  teeth  is  also  considered  by  many  authors  *  to  be  rather 
characteristic  for  digitalis.    While  the  comimercial  drug  will  yield 
