154 
THE  SUGAR  OF  THE  FUTURE. 
the  view  of  preventing  the  otherwise  too  rapidly  proceeding  fer- 
mentation of  the  juice  under  the  joint  influence  of  a  warm  cli- 
mate, and  the  presence  in  the  juice  of  a  nitrogenous  substance. 
The  juice  so  obtained  is  immediately  poured  into  shallow  iron 
pans,  heated  by  fire  and  inspissated  by  evaporation,  until  a  drop 
of  the  liquid,  exposed  to  cold  by  allowing  it  to  fall  on  a  cool 
surface,  becomes  solidified  ;  if  the  desired  degree  of  inspissation 
has  been  obtained,  as  evidenced  by  this  experiment,  the  whole 
contents  of  the  pan  is  cast  into  the  shape  of  big  cylindrical 
lozenges.  Many  thousands  of  pounds  of  sugar  are  annually 
obtained  in  this  very  primitive  manner.  I  collected  in  a  clean 
glass  bottle  a  portion  of  the  juice,  and  found  that  the  unaltered 
juice  does  not  contain  any  glucose  at  all,  but  it  contains  a  ni- 
trogenous principle  which,  aided  by  the  warm  climate,  soon 
causes  the  conversion  of  a  portion  of  the  cane-sugar  of  the  juice 
into  glucose.  In  order  to  prove,  without  the  aid  of  any  very 
artificial  means,  that  the  juice  of  the  Aren  palm  contains  pure 
cane-sugar,  I  collected  a  portion  of  juice  exuding  from  the  tree, 
allowing  it  directly  to  flow  into  alcohol ;  by  these  means  the  ni- 
trogenous principle  alluded  to  is  at  once  eliminated  by  coagula- 
tion. I  thus  obtained  a  mixture  of  equal  parts  of  juice  and  al- 
cohol ;  after  filtration,  this  mixture  was  evaporated  on  a  water- 
bath  to  the  consistency  of  a  syrup.  This  syrup  I  took  along 
with  me  on  my  journey  from  Java  home,  and  during  the  journey 
the  concentrated  syrup  became  solidified,  exhibiting  rare  and 
beautifully  well-defined  crystals  of  cane-sugar,  which,  by  every 
connoisseur,  were  immediately  recognised.  At  the  Congress  at 
Giessen  I  have  spoken  about  the  manufacture  of  sugar  from  palm 
trees  as  the  only  rational  mode  of  obtaining  sugar  in  future, 
upon  the  following  grounds  : — Sugar,  per  se,  consisting,  as  it 
does  in  a  pure  state,  solely  of  carbon,  hydrogen  and  oxygen, 
does  not  withdraw  from  the  soil  anything,  but  the  plants  now-a- 
days  mainly  cultivated  for  obtaining  sugar  therefrom — viz.,  the 
Beta  vulgaris  and  Canna  indica — want  for  their  growth  a  large 
proportion  of  substances  from  the  soil  in  which  they  are  grown 
for  their  sustenance  ;  hence  their  culture  impoverishes  the  soil. 
This,  however,  is  not  the  least  evil,  for  what  is  worse  is,  that 
the  space  now  occupied  by  beet-root  in  Europe,  and  by  sugar- 
cane in  the  tropics,  might  and  ought  to  serve  for  the  growing  of 
