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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  The 
  sources 
  of 
  the 
  raw 
  rubber 
  were 
  not 
  stated, 
  but 
  even 
  Brazilian 
  

   rubber 
  of 
  that 
  period 
  came 
  mostly 
  from 
  Castilla. 
  Methods 
  of 
  treating 
  

   rubber 
  in 
  England 
  may 
  have 
  involved 
  heating 
  it 
  enough 
  to 
  destroy 
  

   the 
  enzyme. 
  Nothing 
  was 
  said 
  of 
  rubber 
  being 
  sticky. 
  

  

  A 
  discovery 
  made 
  in 
  Haiti 
  in 
  1930 
  in 
  relation 
  to 
  the 
  enzyme 
  of 
  

   Castilla 
  showed 
  that 
  the 
  enzyme 
  may 
  be 
  destroyed 
  while 
  the 
  latex 
  is 
  

   still 
  in 
  the 
  bark. 
  Abundant 
  threads 
  of 
  elastic 
  rubber 
  were 
  found 
  that 
  

   separated 
  readily 
  from 
  the 
  decaying 
  bark 
  of 
  Castilla 
  logs, 
  known 
  to 
  

   have 
  been 
  felled 
  nearly 
  3 
  years 
  before. 
  The 
  usual 
  failure 
  of 
  proper 
  

   coagulation 
  to 
  take 
  place 
  in 
  the 
  bark 
  may 
  be 
  ascribed 
  to 
  the 
  oxidizing 
  

   enzyme, 
  and 
  the 
  exceptional 
  occurrence 
  of 
  good 
  rubber 
  was 
  ascribed 
  

   to 
  the 
  fact 
  that 
  the 
  logs 
  had 
  not 
  been 
  shaded 
  but 
  lay 
  in 
  an 
  open 
  place 
  

   where 
  the 
  trees 
  had 
  stood. 
  

  

  The 
  pertinence 
  of 
  the 
  expression 
  "oxidizing 
  enzyme" 
  is 
  appreci- 
  

   ated 
  when 
  it 
  is 
  known 
  that 
  the 
  Castilla 
  latex 
  as 
  it 
  flows 
  from 
  the 
  tree 
  

   will 
  retain 
  its 
  creamy 
  color 
  and 
  show 
  no 
  separation 
  of 
  the 
  rubber 
  

   material 
  if 
  kept 
  from 
  the 
  air 
  by 
  being 
  corked 
  in 
  a 
  glass 
  bottle. 
  Fara- 
  

   day 
  had 
  a 
  bottle 
  of 
  rubber 
  latex 
  from 
  southern 
  Mexico 
  which 
  is 
  said 
  

   to 
  have 
  reached 
  England 
  very 
  nearly 
  in 
  the 
  same 
  state 
  in 
  which 
  it 
  

   came 
  from 
  the 
  tree 
  ; 
  a 
  slight 
  film 
  of 
  solid 
  caoutchouc 
  had 
  formed 
  on 
  

   the 
  surface 
  of 
  the 
  cork 
  which 
  closed 
  the 
  bottle. 
  Efforts 
  have 
  been 
  

   made 
  in 
  the 
  present 
  century 
  to 
  ship 
  Castilla 
  latex 
  to 
  the 
  United 
  States 
  

   in 
  tin 
  cans, 
  but 
  the 
  latex 
  blackened 
  and 
  spoiled, 
  or 
  the 
  rubber 
  coagu- 
  

   lated, 
  as 
  it 
  does 
  in 
  bottles 
  when 
  not 
  corked. 
  

  

  LATEX 
  SEPARATE 
  FROM 
  SAP 
  

  

  Another 
  fact 
  relating 
  to 
  the 
  enzyme 
  was 
  discovered 
  in 
  June 
  1907 
  

   in 
  experimental 
  tapping 
  of 
  Castilla 
  trees 
  in 
  eastern 
  Guatemala, 
  on 
  

   the 
  Trece 
  Aguas 
  estate 
  near 
  Senahu 
  between 
  Panzos 
  and 
  Cahabon. 
  

   It 
  was 
  noted 
  that 
  occasional 
  drops 
  of 
  latex 
  exuded 
  from 
  the 
  surfaces 
  

   of 
  the 
  tapping 
  wounds 
  after 
  removal 
  of 
  the 
  scrap 
  rubber, 
  and 
  that 
  

   these 
  drops 
  did 
  not 
  show 
  the 
  usual 
  separation 
  of 
  a 
  brown 
  liquid, 
  nor 
  

   the 
  usual 
  staining 
  of 
  the 
  rubber. 
  

  

  These 
  creamy 
  white 
  drops 
  were 
  observed 
  repeatedly 
  during 
  the 
  day, 
  

   but 
  no 
  discoloration 
  took 
  place, 
  and 
  the 
  latex 
  eventually 
  coagulated 
  

   without 
  darkening. 
  The 
  drops 
  resulted, 
  obviously, 
  from 
  the 
  loss 
  by 
  

   the 
  latex 
  tubes 
  of 
  their 
  plugs 
  of 
  coagulated 
  rubber 
  when 
  the 
  "scrap" 
  

   was 
  pulled 
  from 
  the 
  cuts. 
  Considering 
  these 
  drops 
  as 
  samples 
  of 
  the 
  

   latex 
  as 
  it 
  exists 
  in 
  the 
  tubes, 
  the 
  failure 
  to 
  show 
  any 
  of 
  the 
  discolor- 
  

   ing 
  fluid 
  that 
  gradually 
  separates 
  from 
  latex 
  in 
  the 
  tapping 
  cuts 
  of 
  

   Castilla 
  was 
  specially 
  noted. 
  Thus 
  the 
  behavior 
  of 
  these 
  nonstain- 
  

   ing 
  drops 
  of 
  latex 
  brought 
  into 
  question 
  the 
  general 
  assumption 
  that 
  

   the 
  enzyme 
  is 
  a 
  normal 
  constituent 
  of 
  the 
  latex 
  of 
  the 
  Castilla 
  tree. 
  

   It 
  is 
  known, 
  of 
  course, 
  that 
  the 
  latex 
  tubes 
  are 
  separate 
  from 
  the 
  other 
  

  

  