304  Examination  of  Commercial  Ginger.  {Am,juiyr/i9£arm' 
When  grown  for  commercial  purposes,  the  plant  is  propagated 
from  cuttings  of  the  rhizomes.  In  India  great  care  is  bestowed  upon 
this  crop,  special  attention  being  given  both  to  the  physical  condi- 
tion of  the  soil  and  its  composition.  Frequently  the  Dolichos  vine 
is  grown  along  with  the  ginger  plants  to  keep  the  ground  moist  and 
cool,  or  the  plants  are  protected  by  a  leafy  covering.  The  cuttings 
are  planted  in  April  or  May,  or  later,  according  to  locality,  and  it 
takes  about  nine  months  for  the  plant  to  reach  maturity.  In  Jamaica 
the  planting  season  begins  in  March  or  April. 
When  the  overground  parts  of  the  plants  die  down,  the  rhizomes 
are  dug  and  variously  treated  to  prepare  them  for  market.  In 
Jamaica,  according  to  Kilmer,5  the  rhizomes  are  first  peeled 
and  then  washed  with  clean  water,  in  some  cases  lime-juice  being 
added  to  the  water,  after  which  they  are  dried  in  the  sun.  In  India 
the  rhizomes  are  usually  partly  peeled  and  treated  with  boiling 
water,  or,  according  to  Simmonds,6  with  boiling  lime  water.  In 
some  cases  the  peeled  rhizomes  are  subsequently  coated  with  calcium 
carbonate  (chalk)  or  calcium  sulphate  (gypsum)  to  prevent  the 
ravages  of  insects.  Decorticated  ginger  is  often  bleached,  by  the 
use  of  chlorinated  lime  or  sulphurous  acid. 
The  rhizome  is  described  as  being  a  sympodium,  that  is,  belongs 
to  the  dichotomous  system  of  branching,  in  which  the  branches  on 
one  side  are  less  developed.  Its  external  morphology,  as  well 
as  histology,  has  been  studied  by  Meyer,7  and  by  Oesterle 
and  Tschirch.8  The  rhizome  is  flattened,  and  as  a  result  of  its 
branching  habit  assumes  the  peculiar  form  sometimes  spoken  of  as 
a  "  hand,"  the  branches  being  called  "  fingers." 
DESCRIPTION  OF  COMMERCIAL  GINGERS. 
Gingers  are  known  commercially  as  "  scraped  "  or  "  decorticated," 
and  "  coated,"  the  scraped  including  those  sorts  from  which  the 
cortex  has  been  removed  in  whole  or  in  part  by  peeling,  as  the 
Cochin,  Jamaica  and  Japan  gingers ;  whereas  the  coated  gingers 
include  those  which  retain  the  periderm  or  outer  natural-  layers  of 
the  rhizomes,  as  African,  Calcutta  and  Calicut.  "  Bleached  "  and 
"  unbleached "  sorts  are  also  distinguished,  the  former  including 
rhizomes  which  are  lighter  in  color,  owing  to  careful  washing  and 
drying  or  other  treatment  as  already  stated.  There  has  long  been 
a  demand  for  "  white  ginger,"  which  demand  has  been  met  by  coat- 
