308  Examination  of  Commercial  Ginger.     { Am  jJu°iy^f0h&  rm' 
fracture  is  short  and  smooth.  The  color  internally  is  light  yellowish- 
brown,  showing  few  reddish-yellow  resin  dots  under  a  lens.  The 
odor  is  very  aromatic  and  the  taste  agreeably  pungent. 
Japanese  Ginger. — The  pieces  are  sparingly  branched  and  vary 
from  2  to  4  cm.  long,  and  from  10  to  20  mm.  in  width.  The  peri- 
derm is  mostly  removed,  the  surface  being  smooth  and  of  a  whitish 
color,  due  to  the  presence  of  a  coating  of  calcium  carbonate.  The 
fracture  is  short  and  very  mealy,  the  color  internally  varying  from 
cream  to  light  brown.  Under  the  lens  the  sections  exhibit  reddish 
resin  dots.    The  odor  is  aromatic  and  the  taste  is  acrid. 
MICROSCOPIC  STRUCTURE. 
The  ginger  rhizome  has  the  typical  monocotyledonous  stem 
structure  [Fig.  2).  It  consists  chiefly  of  parenchyma  containing 
starch,  among  the  cells  of  which  are  numerous  secretion  cells  with 
suberized  walls  that  contain  oil  and  resinous  substances,  and  about 
one-third  to  one-fourth  as  many  fibrovascular  bundles,  which  are  of 
the  closed  collateral  type.  Separating  the  central  cylinder,  or  stele, 
from  the  cortex,  is  a  more  or  less  interrupted  endodermis,  the  radial 
walls  of  the  cells  of  which  are  slightly  suberized,  but  in  the  dried 
material  it  is  distinguished  with  some  difficulty.  A  portion  of  the 
cork  is  found  in  African,  Calcutta,  Calicut  and  Cochin  gingers,  but 
is  wanting  in  the  Jamaica  and  japan  varieties. 
Parenchyma. — The  parenchyma  cells  are  nearly  isodiametric, 
varying  from  25  to  120  /jl  in  diameter,  and  are  somewhat  elongated. 
The  walls  are  composed  of  cellulose  and  are  about  1  fx  thick.  The 
parenchyma  cells  of  the  stele  are  uniformly  larger  than  those  of  the 
cortex.  It  has  been  stated  that  the  parenchyma  contains  calcium 
oxalate,  but  this  substance  has  not  been  detected  in  the  commercial 
sorts  included  in  this  examination,  the  cells  containing  starch  as 
already  stated. 
Starch  Grains. — The  careful  study  of  the  starch  grains  of  ginger 
is  very  important,  for  not  only  may  the  different  commercial  sorts 
be  distinguished  by  the  characters  of  the  starch  grains,  but  their 
appearance  also  possibly  throws  some  light  on  the  manner  of  curing 
of  the  rhizomes.  While  it  is  true  that  the  starch  grains  vary  con- 
siderably in  the  same  ginger  as  well  as  in  the  different  gingers,  still 
they  possess  some  dominant  characters  which  serve  to  distinguish 
to  a  certain  extent  the  different  commercial  gingers.    In  a  general 
