Maruh  2,  i896.]  Supplement  to  the  “ Jropical  Agriculturist' 
653 
the  juices  from  the  halm  which  withers  and  turns 
yellow.  A common  means  of  riddance  is  the 
smoking  of  fields  by  burning  vegetable  refuse  to 
windward.  As  much  as  three-fourths  of  a crop  is 
destroyed  by  this  insect. 
Mispa  cenescens  is  another  rice  pest  widely  dis- 
tributed through  India.  It  is  a beetle  belonging 
to  the  family  Chrysomelid*,  almost  all  the  species 
of  which  feed  on  leaves,  both  in  the  larval  and 
mature  stage,  by  far  the  greater  part  of  the 
damage  being  done  by  larvte.  -Mr.  Coates  of  the 
Indian  Museum  writes  thus  of  this  pest : — “From 
the  reports  that  have  been  recsived,  it  seems  that 
the  pest  appears  often  in  large  numbers  during 
the  rains,  when  the  rice  has  just  been  planted 
out,  and  is  still  young  and  tender,  the  insect  feed- 
ing on  the  parenchyma  of  the  leaves  and  stalks, 
leaving  the  fibre  exposed  so  as  to  give  the  plants 
a white  and  withered  appearance.  Tlie  effect  of 
the  pest  would  seem  to  be  to  stunt  and  weaken 
the  plants  and  cause  them  to  yield  but  a 
small  crop.”  The  crop  is  apparently  in  no  case 
completely  destroyed  by  the  insect,  but  the  out- 
turn may  be  reduced  by  from  twelve  to  fifty  per 
cent.  The  two  common  remdies  against  this  pest 
are  (1)  smoking  out  the  insects  by  burning  paddy- 
straw  covered  over  with  green  leaves,  and  (2) 
letting  out  the  water  from  the  fields.  The  latter, 
where  practicable,  is  recommended  by  Mr.  Coates, 
as  it  appears  that  only  paddy  which  is  almost 
completely  submerged  is  attacked. 
{To  be  continued  ) 
THE  NUTRITIVE  PROCESS  IN  PLANTS. 
MMnaaa  t 
(Pbofessoh  J.  Reynolds  Guf.en,  d.sc.,  f.  b.  s.) 
There  seem  at  first  sight  to  be  very  great  and 
almost  characteristic  differences  between  plant.s  and 
animals  in  regard  to  their  methods  of  nutrition. 
The  food  materials  which  the  several  organism- 
avail  themselves  of  are  at  the  outset  very  differs 
ent,  so  simple  in  the  one  case,  so  complex  in  the 
other.  The  regularity  with  which  the  animal 
takes'in  nourishment  at  fairly  constant  intervals 
contrasts  strongly  with  the  long  periods  of  ab- 
sorption varied  by  long  and  irregular  ])eriods  of 
iutermittance  which  are  characteristic  of  the 
plant.  Yet  when  we  come  to  study  the  details 
of  the  nourishment  of  the  actual  living  sub- 
stance of  the  plant,  as  distinguished  from  the 
absorption  of  the  raw  materials  of  which  that 
nourishment  is  composed,  the  difference  almo.st 
disappears.  The  study  of  the  chemical  process 
which  go  on  in  plants,  or  as  it  is  technically 
called  their  metabolism,  shows  us  that  the  appar- 
ent process  of  feeding,  the  absorption  of  very  sim- 
ple compounds  from  the  air  and  from  the  soil,  is 
not  the  feeding  or  administering  of  nourishment 
itself,  but  only  a preliminary  operation,  enabling 
the  living  substance  of  the  plant  to  construct  its 
pabulum  from  these  simple  bodies,  the  pabulum 
really  being  a.s  complex  as  that  on  which  an  animal 
is  nourished,  and  consisting  of  almost  the  same  sub- 
stances, at  any  rate  of  bodies  which  correspond 
very  closely  to  those  of  the  animal  diet.  In  other 
words  both  classes  of  organism  feed  upon  the  same 
or  corresponding  substances,  the  animal  absorbing 
them  from  the  exterior  in  a state  in  which  they  are 
almost  fitted  to  nourish  its  living  substances,  the 
plant  taking  them  in  such  a condition  that  an 
enormous  amount  of  preliminary  constructive 
work  has  to  be  expended  upon  them  before  they 
are  of  nutritive  value,  this  constructive  work  be- 
ing the  formation  from  the  simple  bodies  ab- 
sorbed— of  materials  such  as  the  animal  absorbs 
directly  as  its  food.  The  difference  between  them 
thus  becomes  at  the  outset  one  of  con-'iderable 
interest.  It  is  not  that  the  protoplasm  of  the 
animal  needs  different  food  from  that  of  the  vege- 
table ; it  is  rather  that  while  in  both  cases  chemi- 
cal work  has  to  be  performed  upon  the  absorbed 
material  before  it  can  be  regarded  as  food  in  the 
strict  sense,  that  work  in  the  case  of  an  animal  is 
on  the  whole  a breaking  down  of  complex  bodies, 
but  in  that  of  a vegetable  it  is  a building  up  of 
simpler  ones  till  the  same  .stage  is  reached  in  both 
cases,  namely,  a material  which  protoplasm  or 
living  substance  can  absorb  into  itself,  and  from 
which  it  can  be  constructed. 
But  so  far  as  the  vegetable  organism  is  con- 
cerned, this  is  not  by  any  means  the  whole  story. 
Leaving  aside  for  the  moment  the  cases  of  such 
plants  as  fungi,  which  can  do  nothing  with  the 
food  supply  yielded  to  a normal  green  plant  by 
the  atmospiiere,  we  find  that  the  condition.?  of  lU'e 
of  an  ordinary  green  plant  involve  a great  e.xten- 
sion  of  the  original  constructive  process.  It  has 
no  definite  and  regular  meal  times  at  which  it  can 
take  in  a certain  quantity  of  food  regulated  partly 
by  the  needs  of  the  organism,  and  partly  by  the 
mysterious  factor  which  we  call  appetite.  Its 
absorptive  processes  are  much  more  under  the  in- 
rtuence  of  natural  phenomena,  the  degree  of  light, 
the  amount  of  warmth,  moisture,  &c.  Periods  of 
intermission  of  irregular  length  are  caused  by 
the  alternation  of  day  and  night ; in  the  case  of 
perennial  plants  still  greater  disturbances  are 
caused  by  the  succession  of  the  seasons  of  the 
year,  and  the  alterations  these  pi’oduce  in  the 
amount  of  foliage  which  the  plant  preserves; 
weather  and  its  vicissitudes  form  a series  of  dis- 
turbing infiuence.s.  We  liave  thus  the  certainty  of 
failure  to  survive  in  the  struggle  for  existence 
unless  the  initial  absorptive  and  constructive  pro- 
cess are  supplemented  by  otiiers  which  in  some 
way  shall  make  tlie  organism  indifferent  to  these 
changes  and  irtermission«  of  supply,  and  capable 
of  carrying  out  true  nutritive  work,  tiiough  the 
initial  stages  of  such  workarechecked  or  suspended. 
Such  a secondary  process  involves  the  whole  story 
of  what  it  is  usual  to  call  reserve  materials.  It 
is  evident  to  as  all,  from  a very  general  consider- 
ation of  the  peculiarities  of  the  vegetable  kingdom, 
that  the  constructive  proce.ss  is  very  much  the 
leading  one  in  the  history  of  most  of  its  members. 
Growth  proceeds  for  such  long  periods,  that  there 
is  stored  up  iu  such  a structure  as  a forest  tree  for 
example,  an  enormous  amount  of  material  and  of 
potential  energy.  Tliis  gross  accumulation,  how- 
ever, of  which  as  food  supply  the  organism  makes 
no  use,  must  be  distinguished  from  the  storage  of 
material  intended  for,  and  ultimately  applied  to, 
direct  consumption  by  tlie  plant  in  the  processes 
of  nutrition.  It  is  the  latter  which  constitutes 
the  material  truly  and  properly  called  reserve. 
LIME  IN  AGRICULTURE. 
There  is  perhaps  no  subject  that  is  more  often 
written  about  in  agricultural  publications  than 
the,valiie  of  lime  iu  agriculture,  and  yet  the  im'< 
