2,6o 
Structure  of  Our  Hemlock  Barks. 
Am.  Jour.  Pharm . 
July,  1895. 
as  in  the  other  species.  The  very  close  structural  resemblance  of 
the  barks,  and  the  very  intimate  relationship  of  the  two  species  in 
habit  as  well  as  in  structure,  suggest  that  the  presence  of  starch  in 
the  one  and  its  absence  in  the  other  was  only  a  seasonal  differ- 
Fig.  4. 
ence.  But  this  is  a  point  which  requires  further  investigation.  The 
medullary  rays  in  both  barks  are  composed  of  single  rows  of  cells, 
and  these  are  radially  elongated  and  of  large  size  as  compared  with 
