201 
On  30th  November  I tapped  two  trees  of  the  respective  circum- 
ference of  63  and  60  inches,  obtaining  therefrom  6 lbs.  oz.  of 
rubber.  x\s  to  the  age  of  these  trees  I can  say  nothing,  as  they  are 
wild  trees  growing  on  the  property.  On  3rd  December  I tapped  a 
rubber  tree  planted  by  myself,  age  4 years  4 months,  girth  26 
inches,  height  27  feet,  the  result  being  2^  oz.  of  rubber.  Eight 
days  afterwards  1 again  tapped  the  tree  and  obtained  of  an  ounce 
of  rubber,  making  total  product  3J  ounces.  A few  days  later  I 
tapped  ten  trees,  age  4 years  and  4 montlis,  average  girth  23  inches, 
obtaining  therefrom  22  ounces  of  rubber.  These  trees  could  all 
have  been  bled  again,  the  second  operation  in  no  way  affecting  the 
tree,  as  I have  proved  by  the  first  named  experiment.  In  both 
cases,  the  quality  of  the  rubber  after  preparation  was  excellent. 
On  7th  December,  I tapped  a tree  of  the  age  of  3 years  and 
4 months  : result  f oz.  of  rubber  of  poor  quality,  sticky  and  little 
life  in  it.  It  need  hardly  be  remarked  that  these  experiments  were 
made  not  for  marketable  purposes,  but  in  order  to  see  what  the 
increase  in  yield  might  be  in  each  successive  year. 
In  order  to  compare  these  figures  with  others,  I will  quote  those 
obtained  by  the  writer  of  the  article  previously  referred  to.  Mr. 
Weber  gives  the  following  as  the  results  of  his  experiments  made 
at  Hie  plantation  of  Las  Cascadas  on  the  Isthmus  of  Panama  : — 
Five-year  old  trees,  mean  yield  of  77  trees 
Six-year  „ ,,  ,,  61  „ 
Eight-year  „ ,,  „ 61  ,,, 
Twelve-year  ,,  ,,  ,,  61  ,, 
Per  Tree. 
2*3  oz. 
...  2-0  ,, 
...  1-8  ,, 
•••  T3  » 
Mr.  Weber  states,  and  in  this  I quite  agree,  that  the  tree  can 
with  perfect  safety  be  tapped  twice  yearly  ; thus  the  annual  rubber 
yield  may  be  taken  at  double  that  in  the  last  column  of  the  table. 
He  further  observes  that  he  considers  his  figures  as  rather  below 
than  above  the  mark.  It  will  be  remembered  that  Mr.  Weber 
gives  the  amount  of  rubber  contained  in  the  latex  at  from  26  to  31 
per  cent.  This  is  far  lower  than  I have  ever  obtained.  According 
to  Dr.  UREand  Professor  Far.\day,  the  percentage  of  pure  rubber 
in  the  latex  is  45  per  cent.  I have  never  found  the  milk  of  the 
Castilloa  give  less  than  39  per  cent.,  and  in  one  case,  with  unusually 
thick  milk  from  an  old  much  tapped  tree,  I obtained  as  high  as 
49  per  cent.  If,  then,  we  take  the  yield  of  a 6-year  old  tree  at  i lb. 
13  ounces,  as  given  by  Mr.  Weber,  the  result  would  be  at  40  per 
cent.,  say  oz.  of  rubber,  which  is,  I think,  a perfectly  safe  and 
conservative  estimate.  I have  no  doubt,  as  Mr.  Weber  states, 
that  trees  can  with  perfect  safety  be  tapped  twice  a year,  and 
though  the  yield  may  not  be  doubled,  a very  material  increase  of 
production  will  result. 
My  experiments  have  shown  me  that  trees  that  have  already 
been  bled  yield  their  latex  much  more  freely  than  those  bled  for  the 
first  time.  This  was  most  noticeable  in  operating  on  a number  of 
trees  in  my  own  land,  when  I found  that  the  milk  flowed  more 
readily  and  copiously  from  those  that  had  been  apparently  maltreated 
for  years  than  from  splendid  trunks  which  did  not  bear  a scar.  It  is 
