﻿NATURAL 
  RUBBER 
  — 
  COOK 
  367 
  

  

  ing 
  than 
  the 
  other 
  species 
  of 
  Castillo, 
  in 
  Mexico 
  and 
  Central 
  America, 
  

   since 
  the 
  leaves 
  are 
  smaller, 
  but 
  the 
  trees 
  grow 
  large 
  and 
  yields 
  of 
  

   30 
  to 
  50 
  pounds 
  of 
  rubber 
  are 
  reported. 
  

  

  The 
  confusion 
  of 
  the 
  names 
  might 
  be 
  supposed 
  to 
  have 
  little 
  rela- 
  

   tion 
  to 
  the 
  study 
  of 
  practical 
  problems, 
  since 
  the 
  two 
  types 
  of 
  trees 
  

   are 
  entirely 
  unlike 
  in 
  appearance, 
  habits, 
  and 
  cultural 
  requirements. 
  

   Castilla 
  is 
  a 
  striking, 
  large-leaved 
  tree 
  like 
  a 
  magnolia, 
  while 
  the 
  Para 
  

   rubber 
  has 
  the 
  appearance 
  of 
  an 
  ordinary 
  tree 
  — 
  an 
  ash 
  or 
  a 
  boxelder. 
  

   Although 
  nobody 
  who 
  knows 
  the 
  two 
  trees 
  would 
  be 
  expected 
  to 
  con- 
  

   fuse 
  them, 
  yet 
  much 
  confusion 
  regarding 
  their 
  characters 
  and 
  behavior 
  

   has 
  existed 
  and 
  still 
  continues, 
  even 
  among 
  those 
  concerned 
  with 
  rub- 
  

   ber 
  experiments 
  and 
  projects. 
  The 
  commercial, 
  industrial, 
  mechan- 
  

   ical, 
  and 
  chemical 
  aspects 
  of 
  the 
  rubber 
  problems 
  have 
  been 
  intensively 
  

   elaborated, 
  but 
  not 
  the 
  plant-life 
  aspects. 
  Not 
  many 
  tree 
  crops 
  have 
  

   been 
  domesticated, 
  and 
  people 
  rarely 
  have 
  experience 
  of 
  a 
  kind 
  to 
  

   make 
  them 
  familiar 
  with 
  such 
  differences 
  as 
  those 
  of 
  the 
  rubber 
  trees. 
  

  

  Outside 
  of 
  the 
  Amazon 
  valley, 
  popular 
  knowledge 
  of 
  rubber 
  trees 
  

   in 
  tropical 
  America 
  has 
  related 
  almost 
  entirely 
  to 
  Castilla, 
  with 
  the 
  

   Para 
  rubber 
  tree 
  coming 
  forward 
  only 
  in 
  recent 
  years. 
  The 
  uncon- 
  

   scious 
  carry-over 
  of 
  ideas 
  from 
  the 
  Castilla 
  to 
  the 
  Para 
  rubber 
  has 
  

   occasioned 
  many 
  destructive 
  errors 
  and 
  interferences, 
  even 
  to 
  the 
  ex- 
  

   tent 
  of 
  Para 
  rubber 
  trees 
  being 
  cut 
  down 
  as 
  complete 
  failures 
  because 
  

   they 
  did 
  not 
  yield 
  latex 
  freely 
  like 
  Castilla. 
  This 
  reason 
  was 
  given 
  

   for 
  cutting 
  down 
  several 
  Para 
  rubber 
  trees 
  in 
  an 
  experimental 
  plant- 
  

   ing 
  in 
  Haiti. 
  One 
  of 
  the 
  stumps 
  survived 
  for 
  many 
  years, 
  as 
  shown 
  

   in 
  plate 
  11. 
  

  

  On 
  account 
  of 
  confusion 
  of 
  the 
  trees, 
  a 
  certain 
  indifference 
  appears 
  

   when 
  the 
  planting 
  of 
  Para 
  rubber 
  is 
  advocated 
  by 
  speakers 
  or 
  writers 
  

   not 
  familiar 
  with 
  the 
  Castilla 
  tree. 
  Separate 
  recognition 
  of 
  the 
  two 
  

   trees 
  in 
  the 
  minds 
  of 
  interested 
  people 
  is 
  the 
  first 
  step 
  toward 
  effective 
  

   understanding 
  and 
  utilization 
  of 
  either 
  of 
  the 
  trees 
  in 
  tropical 
  Amer- 
  

   ica, 
  or 
  of 
  both 
  together. 
  Castilla 
  may 
  serve 
  under 
  some 
  conditions 
  

   as 
  a 
  nurse 
  crop 
  for 
  the 
  Para 
  rubber, 
  but 
  the 
  extraction 
  of 
  the 
  latex 
  

   will 
  need 
  to 
  be 
  done 
  in 
  a 
  different 
  way. 
  

  

  COMING 
  OF 
  THE 
  RUBBER 
  AGE 
  

  

  Enormous 
  resources 
  of 
  Para 
  rubber 
  were 
  discovered 
  in 
  the 
  forests 
  

   covering 
  the 
  valleys 
  of 
  the 
  Amazon 
  and 
  its 
  principal 
  tributaries, 
  and 
  

   yet 
  in 
  a 
  few 
  years 
  all 
  the 
  accessible 
  areas 
  were 
  being 
  exploited, 
  more 
  

   wild 
  rubber 
  was 
  being 
  sought 
  in 
  other 
  continents, 
  and 
  the 
  question 
  of 
  

   planting 
  rubber 
  trees 
  was 
  being 
  raised. 
  In 
  1876 
  Wickham 
  made 
  his 
  

   famous 
  shipment 
  of 
  Para 
  rubber 
  seeds 
  to 
  the 
  Kew 
  Gardens 
  near 
  

   London, 
  for 
  planting 
  in 
  India, 
  and 
  20 
  years 
  later 
  the 
  first 
  commercial 
  

   planting 
  of 
  Para 
  rubber 
  was 
  made 
  in 
  Malaya. 
  The 
  search 
  for 
  other 
  

  

  