48 
NOTE  ON  A BOUGH  OF  PARA-RUBBER 
DESTROYED  BY  ROT. 
In  a Para  rubber  tree  in  the  Botanic  Gardens  which  had  several 
erect  branches  at  the  top,  it  was  noticed  that  a good  deal  of  rubber 
had  been  dropping  and  was  still  exuding.  A man  was  sent  up  the 
tree,  and  cut  off  the  bough,  which  was  then  sawn  in  two  to  observe 
the  cause  of  this.  The  bough  is  5I  inches  in  diameter  on  one  side 
(the  outer  one)  a smaller  branch  had  fallen  or  been  broken  off  and 
the  wound  i inch  across  had  not  healed,  but  the  wood  had  decayed 
forming  a space,  7 inches  long  and  3 inches  wide.  Fungi  had 
attacked  the  wood  and  the  decomposition  had  spread  downwards 
for  about  9 inches  and  upwards  for  20  inches.  I'he  bark  on  this 
side  was  nearly  twice  as  thick  as  that  on  the  other  side  (the  inner 
side)  and  was  quite  dry  and  perforated  by  beetles,  which  had  how- 
ever not  penetrated  into  the  living  wood.  The  very  small  beetles, 
belonged  to  the  group  of  shot-borers  which  habitually  feed  on 
dead  wood,  and  from  their  holes  the  rubber  had  exuded.  Here 
and  there  in  the  dead  bark  were  spaces  which  were  filled  with  rub- 
ber but  no  liquid  latex  could  be  seen  in  this  part  of  the  bark.  The 
living  bark  exuded  latex  freely,  but  in  greatest  abundance  just 
above  the  point  to  which  the  death  of  the  wood  had  reached,  and 
much  more  freely  than  from  the  thinner  bark  on  the  inner  side  of 
the  tree.  It  appears  then  that  in  the  case  of  an  injurv  of  this  kind 
the  wood  dies  before  the  bark  covering  it.  .\s  the  death  caused 
by  the  fungus  spreads  vertically  up  or  down  the  stem  the  beetles 
attack  the  decaying  wood  but  do  not  touch  the  living  lissut'.  At  the 
same  time  the  flow  of  latex  to  the  affected  part  increases  so  that 
the  greatest  amount  is  to  be  found  near  the  injury.  'I'his  increase 
of  flow  in  the  neighbourhood  of  an  injury,  corresponds  to  what 
has  been  named  “callingthe  latex.’’  It  is  known  that  the  first 
wound  inflicted  on  a tree  j)roduc(‘S  but  little  milk,  but  when  the 
wound  is  re-opened  daily,  the  flow  gradually  increases.  In  the 
.Amazons  method  of  tapping  described  in  another  arti('Ie,  a cut  is 
made  the  first  day  high  up,  and  next  day  a fresh  one,  two  or  three 
inches  lower,  and  so  on  to  the  foot  of  the  tree,  the  first  wound 
j)roduces  very  little  latex,  th(‘  second  more  and  so  on.  d'his  is  not 
due  to  tin*  fact  that  there  is  mpre  latex  low  down  the  tree  than 
above,  but  rather  due  to  the.  wound  action,  which  appears  to  pro- 
duce a flow  of  latex  to  the  wounded  side  of  the  trunk.  A tree  thus 
is  said  to  milk  better  when  it  is  accustomed  to  it. 
JOURNEY  TO  A RUBBER  PLANTATION  ON  THE 
ISTHMUS  OF  COLUMBIA. 
Bv  Dk.  C.  O. 
The  well  known  difficulty  of  investigating  satisfactorily  in  Europe 
any  of  the  numerous  questions  of  importance  connected  with  the 
collection  of  the  latex  from  the  rubber  trees,  its  composition,  and 
the  most  satisfactory  manner  of  converting  it  into  iiidia  rubber. 
