Auo.  r,  1895.J 
THE  TROPICAL  AGRICULTURIST. 
11 
wc  sliould  know  the  oompositioa  of  t!ic  soil  wo  have 
to  deal  witli  ; also  the  composition  of  mauuies  awd 
the  ash  constituents  of  plants.  We  should  then  bo 
able  to  mix  our  owu  compounds  to  suit  plants 
under  our  care.  In  conclusion  I may  say  that  of 
all  the  elements  essential  for  plant  life  nitrogen 
is  the  most  important.  It  is  one  of  the  chief 
elements  of  protoplasm,  and  this  is  the  substance 
which  gives  life  to  plants.— n'ad  hii  Mr.  ■/. 
Gay,  rtf  a meet  inf)  of  the  Wovinlen  and  Dint  riel  llorli- 
eiiltunU  iioeietij  ).— Journal  of  llorticultare. 
THE  VITALITY  OF  SEEDS. 
In  the  course  of  his  investigations  on  the  behaviour 
of  matter  at  low  temperatures,  Professor  Dewar 
was  led  to  consider  the  effect  of  great  cold  on 
bacterial  life  and  seeds.  Although  bacterial  life  is 
destroyed  by  boiling  in  water  at  a temperature  of 
100^  0.,  it  can  still  endure  unaffected  a degree  of 
cold  much  greater  in  proportion.  Professor  Dewar 
submitted  seeds  for  the  space  of  an  hour  to  a 
temperature  of  18'2o  G.,  and  found  that  they  after- 
wards went  on  putrefying  or  germinating  as  the  case 
happened  to  be.  In  a moment  of  scientific  inspiration, 
liOrd  Kelvin  suggested  that  the  first  life  might  have 
been  brought  to  this  planet  by  a seed-bearing 
meleorite.  Put  though  it  has  yet  to  bo  explained 
how  this  meteorite  was  ever  originally  equipped 
with  seeds,  the  discoveries  of  I’rof.  Dewar  are 
interesiing  in  a way  because  they  give  colour  to 
Lord  Kelvin’s  theory.  They  show  that  spores  may 
live  upon  a planet  through  long  periods  of  low 
temperature.  The  popular  press  is  never  tired  of 
trumping  up  the  old  stories  of  the  power  of  mummy- 
wheat  to  germinate  after  long  ages  of  time.  Let 
it  sutlicd  to  say  that  these  exaggerated  estimates 
of  the  powers  of  retaining  vitality  which  seeds 
possess,  have  not  been  substantiated. 
In  a recent  number  of  that  interesting  journal. 
Science  O'osnii),  Mr.  H.  P.  Guppy  put  forward  a pro- 
posal which  we  commend  to  all  who  are  int  rested 
in  biological  science.  In  his  investigations  on  the 
dispersal  of  seeds,  Darwin  came  to  the  conclu.-ion 
that  a period  of  twenty-four  hours  as  the  limit  of 
time,  and  oOO  miles  as  the  limit  of  distance,  was 
the  most  that  could  reasonably  be  permitted  to  the 
agency  of  birds  in  stocking  islands  with  seeds  carried 
either  on  or  inside  their  bodies.  Mr.  Guppy  sug- 
gests tha't  observers  should  examine  such  specimens 
of  water-fowl  as  are  common  in  their  neighbour- 
hood in  order  that  we  may  have  more  definite 
data  as  to  the  dispersal  of  seeds  and  their  vitality. 
Some  observers  have  testified  to  the  fact  that 
wild  ducks  frequently  carry  seeds  a distance  of 
perhaps  a thousand  miles  or  more,  and  that  these 
seeds  retain  their  vitality  and  germinate,  sometimes 
without  much  delay,  at  other  times  after  a year 
or  two.  We  know  that  the  common  European 
species,  Xanthium  spinosum,  has  spread  over  the 
whole  of  South  Africa,  and  we  are  pr.bably  light 
in  thinking  that  the  seeds  of  this  plant  have  been 
carried  in  the  wool  of  sheep.  Here  the  teed  did 
not,  as  in  the  case  of  the  water-fowl,  pisi  into 
the  stomach  of  the  animal,  but  there  seems  to  bo 
no  reason  why  birds  should  not  transport  sreds 
ill  their  internal  orgvus  across  oceans  and  continents. 
Modern  experiments  with  the  seeds  of  cereals  show 
that  they  lose  their  vitality  after  ten  years  at  most, 
and  usually  much  sooner  ; but  much  depeuds  on  the 
state  of  the  se.ds,  ai  the  time  they  are  gathered 
from  the  parent  plant,  the  mode  of  preservation, 
and  the  influences  they  may  have  Been  exposed  to 
during  preservation,  ftir.  Sewerby,  who  has,  at  the 
garden  of  the  Royal  Botanic  Society,  in  Regent’s 
Park,  experimented  with  a variety  of  seeds  of  various 
ages,  and  produced  in  quite  distinct  countries,  de- 
clares that  he  has  not  met  with  any  of  fifteen  years 
of  age,  to  his  own  knowledge,  to  grow.  The  most 
aged  seeds  ho  has  known  to  vegetate  were  t'lose  of 
the  Australian  Baobab  Tree  (Adansonia  Gregorii). 
ten  years  old.  One  of  the  most  cu:  ions  ca-es  of  the 
vitality  of  seeds  is  reported  in  the  Journal  of  the 
Royal  Botanic  Society  for  188.5.  A handful  of  fruits 
of  Aucuba,  taken  from  a shrub  iu  the  gardens  at 
Regent’s  Park,  were  planted  in  a pot  in  July,  1882; 
two  plants  appeared  above  ground  in  February,  188.’! 
fourteen  iu  1885,  and  two  more  in  February  I88G. 
It  may,  perhaps,  be  found  that  the  process  of  ripening 
after  the  fruit  has  been  removed  from  the  parent, 
especia  ly  when  buried  in  moist  earth  and  at  a 
less  rapid  pace,  may  account  for  the  difference  iu 
time  of  germinating. 
Another  point  on  which  mori  light  is  wanted  is 
the  vitality  of  seeds  after  being  carried  over  lonc' 
distances  by  winds.  Of  course,  with  Cryptogama 
the  matter  is  easy  enough,  for  we  have  in  the  °viud 
an  ugeucy  capable  of  distributing  spores  over  long 
distances  ; but  with  phanerogamous  plants  difficulties 
arise.  Berthelot.  indeed,  avers  that  after  a violent 
hurricane  he  saw  an  annual  belonging  to  the  Gom- 
positiu  (Brigeron  ambiguus),  widely  distributed 
t roughout  the  Mediterranean  region,  suddenly 
app.ar  at  v.irious  spots  on  the  Ganary  Islands, 
where  it  was  previously  unknown.  It  is  probable, 
therefore,  that  the  seed  had  been  blown  across  from 
Portugal  or  North  Africa.  How  interesting  would 
i;  be  if  wc  could  place  a mark  on  csrtain  seeds, 
and  casting  them  to  the  winds,  find  the  identical 
ones  in  some  spot  hundreds  of  miles  away  from  home  ! 
The  dr.entnrcrt  of  a Seed.  What  a sale  such  a book 
would  have  among  botanists  and  biologists  I 
Darwin’s  experiments  to  deter. nine  the  vitality  of 
seeds  in  sea-water,  the  lesults  of  which  were 
published  iu  thii  .Journal,  do  not-  seem  to  have 
been  imitated  by  more  recent  investigators;  but 
here  surely  is  an  interesting  field  for  study.  We 
may  perhaps  be  allowed  to  quote  one  of  the  ex- 
periments. Darwin  found  that  out  of  eighty-seven 
Kinds  of  seeds,  sixty-four  germinated  after  an 
immersion  of  twenty-eight  days,  and  a few  survived  an 
immersion  of  187  days ; and  in  another,  that  out 
of  ninety-four  dried  plants,  eighteen  floated  for 
abjve  twenty-eight  days.  Gombiuing  the  results  of 
the  two  experiments,  Daiwiu  concluded  that  four- 
teen plants  out  of  every  100  in  the  flora  of  a country 
might  be  tloaced  by  currents  moving  at  the  average 
rate  of  the  several  Atlantic  current  i,  a distance  of 
92 1 miles,  and  might,  on  being  stranded,  furnish 
seeds  capable  of  germinating. 
Whi.e  on  the  subject  of  the  power  of  seed.s  to 
withstand  the  power  of  water,  it  may  not  be  unin- 
teresting to  state  that  it  is  a well-known  fact  that 
the  Goco-nut  is  one  of  the  first  plants  to  make  it) 
appearance  on  coral  islands,  and  it  is,  according  to 
Sir  John  Lubbock,  the  o ily  Palm  which  is  common 
to  both  hemispheres.  The  seeds  of  the  Goco-nut 
are,  of  courde,  well  protected  against  mishaps  by 
the  loose  texture  of  their  husks,  and  can  float  easily 
on  the  water.  The  seeds  of  the  common  Duck- 
weed, again,  lie  dormant  at  the  bottom  of  the  water 
all  through  the  long  autumn  and  winter,  but  at 
the  approach  of  spring  they  rise  to  the  surface  with 
unimpaired  vitality,  and  germinate  forthwith. 
Some  years  ago  the  British  Association  took  up 
the  question  of  the  vitality  of  seeds,  and  instituted 
a series  of  experiments,  iu  which  Professors  Daubeny, 
Henslovv,  and  Bindley  took  part.  In  th  i Report 
for  1857  we  find  a valuable  summary  of  the  results 
of  the  experiments  fiom  1841  10  1857  inclusive.  In 
the  table  showing  the  greatest  ages  at  wuich  the 
seeds  experimente  1 with  germinated,  we  find  that 
the  seed  of  a species  of  Golutea  belonging  to  the 
Lsguminosae  germinated  after  forty-tnree  years. 
This  is  the  only  plant  mentioned  in  the  list  whose 
seed  preserved  its  vitality  for  so  lo  g a time  as 
forty-tiiree  years,  though  it  would  appear  in  general 
that  the  seeds  of  leguminoui  plants  retain  their 
vitality  for  a long  time. 
We  are  unaware  that  any  experiments  are  being 
carried  on  at  the  pres;nt  time  on  this  interesting 
subject ; certainly  the  British  Association  dropped 
the  matter  after  the  year  1857. 
De  Candolle  in  1816,  experimenting  with  seeds 
about  15  years  old,  obtained  results  which  go  to 
prove  that  the  natural  orders,  Malvacece  and  Legu- 
minosae  excel  all  the  orders  ex  unined  iu  the  duration 
of  the  faculty  of  germination.  Comparing  these 
results  with  those  obtained  by  the  British  Associa- 
tion investigations,  we  find  that  the  longest  period 
a epeciea  Malyaceto  letained  its  vitality  W4i4  21 
