As"ptXvfih9i3m!}  Cells  °f  Aconite  Root.  393 
value;  ceils  vary  in  length  from  51  to  391  mikrons  and  from  34 
to  102  mikrons  in  breadth,  eliminating  the  exceedingly  large  ones 
which  are  only  occasionally  met  with,  the  most  constant  dimentions 
would  average  119  mikrons  in  length  and  70  mikrons  in  breadth. 
The  cell  wall  with  an  aqueous-glycerin  solution  of  chloral 
hydrate,  freshly  mounted,  in  many  cases  showed  a  striate  or  homo- 
genous structure,  while  in  old  mounts  the  wall  was  traversed  by  a 
few  or  many  canals ;  in  some  the  fissures  were  very  prominent, 
appearing  as  if  the  cell  wall  was  composed  of  beads  or  distinct 
segments.  Fig.  Ill,  figure  (j).  Thickness  of  wall  from  8  to  25 
mikrons  the  average  being  from  8  to  12  mikrons. 
The  outline  of  the  lumen  in  most  of  the  samples  was  smooth 
or  slightly  irregular,  one  sample  showed  a  marked  deviation  from 
the  others,  being  deeply  ragged  and  angular.  Fig.  IV,  figures  (h), 
(k),  (1)  and  (o). 
The  number  of  stone  cells,  prominence  of  fissures  and  the  out- 
line of  the  lumen  seems  to  vary  considerably  in  different  samples. 
From  the  above  illustrations  may  be  seen  that  the  elements  vary 
greatly  in  form,  in  fact  so  much  so  that  it  is  practically  impossible 
to  say  which  are  characteristic. 
While  the  writer  chose  the  stone  cells  of  Aconite  as  a  type  to 
show  the  great  diversity  in  shape  and  structure,  he  did  so  only  as 
a  means  to  introduce  the  subject  of  a  more  careful  restudy  of  plant 
elements  from  the  diagnostic  point  of  view ;  that  the  beginner 
should  not  gather  his  information  from  one  sample,  but  by  the 
careful  examination  of  many;  let  us  not  in  text  books  and  articles 
sacrifice  accuracy  for  briefness ;  much  rather  would  I  see  an  article 
profusely  illustrated,  allowing  the  worker  to  see  the  variations, 
than  one  or  two  characteristic  (?)  ones. 
It  is  only  after  one  is  thrown  on  his  own  resources  and  where 
accuracy  is  required  that  one  can  appreciate  the  situation. 
Laboratory  of  Botany  and  Pharmacognosy, 
Cleveland  School  of  Pharmacy, 
Western  Reserve  University,  Cleveland,  Ohio. 
