55 
cut  in  the  horizontal  direction.  Compared  with  the  total  number 
of  milk-ducts  in  the  layer  of  bast  surrounding  the  cambium,  the 
former  number  is,  of  course,  insignificantly  small.  Moreover,  we 
must  bear  in  mind  that  the  latex  is  held  in  the  milk-duels  by  capil- 
lary force,  and  in  order  to  obtain  a flow  of  it  from  any  incision  we 
largely  depend  upon  the  pressure  exerted  upon  these  milk-duels 
by  the  turgescence  of  the  cellulose  tissues  of  the  tree.  It  will 
readily  be  seen  that  a vertical  incision  largely  relieves  this  pressure, 
and  consequently  the  flow  of  latex  obtainable  by  such  an  incision 
will  not  even  be  proportional  to  the  number  of  milk-ducts,  however 
small,  which  have  been  cut  into. 
On  the  other  hand  very  little  reflection  will  show  that  in  applying 
a horizontaKincision,  not  only  do  we  open  all  the  milk-ducts  run- 
ning through  the  ar*  a defined  by  that  incision,  but  moreover  the 
pressure  due  to  the  above  mentioned  turgescence  is  not  in  the  least 
interfered  with,  and  assists  materially  in  producing  a most  copious 
flow  of  latex.  It  would  therefore  appear  to  follow  that  while  verti- 
cal cuts  are  entirely  useless,  at  any  rate,  as  far  as  Castilloa  elastica 
is  concerned,  horizontal  cuts  produce  the  maximum  flow  of  latex, 
and  a system  of  horizontal  cuts  therefore  offers  the  best  prospects 
for  an  effectually  tapping  of  the  trees.  This,  no  doubt  is  so,  but 
the  circumstance  must  not  be  overlooked  that  a horizontal  cut  is 
not  very  satisfactory  for  the  gathering  up  of  the  exuding  latex,  this 
particularly  in  conjunction  with  the  fact  that  a Castilloa  tree  cannot 
be  drained  by  a single  small  horizontal  cut  as  is,  for  instance,  the 
case  with  Hevea,  but  requires  a whole  series  of  cuts.  This  renders 
it  desirable  that  instead  of  tapping  Castilloa  with  a number  of  small 
cuts  a continuous  cut  would  be  preferable  and  one  which  drains 
practically  the  whole  area  of  the  trunk.  'I'here  is  only  one  cut  of 
this  description,  and  this  is  the  one  known  as  the  spiral  cut  which 
indeed,  has  ahvays  been  laro;ely  employed  by  the  native  collectors 
exploiting  Castilloa  trees.  I have  indeed  satisfied  myself  that  the 
flow  of  latex  obtainable  from  a spiral  cut  applied  at  angle  of  not 
more  than  45  degrees  produces  excellent  results  as  far  as  the  flow 
of  latex  is  concerned. 
There  is  also  the  repeatedly  advocated  system  of  an  ascending 
series  of  V.  shaped  c uts,  the  apices  of  which  are  connected  by  a 
a vertical  cut  which  serves  as  a channel  down  w hich  the  milk  is 
enabled  to  flow.  In  the  first  instance,  1 consider  this  vertical  cut 
objectionable,  as,  while  it  defaces  the  tree,  it  docs  not  contribute 
to  the  yield  of  latex  obtained.  Moreover,  in  the  case  of  the  Cas- 
tilloa trees  at  L.as  Cascadas  this  vertical  cut  would  b(^  quite  useless 
as  the  latex  yielded  by  the  trees  issues  from  the  cuts  as  a thick 
cream  which  does  not  flow,  so  that  in  this  case  the  V.  shaped  cuts 
would  only  about  have  the  effect  of  a double  system  of  crossing 
spiral  cuts. 
The  next  question  to  be  settled  was  the  tool  with  which  the 
above  named  spiral  cuts  are  to  be  applied.  'The  instrument  in 
universal  use  for  this  pur[)Ose  throughout  Central  America  is  the 
machete^  a sort  cf  cutlass.  I'his  forinidable  tool  requires  verv  dex- 
terous handling  in  order  to  produce  a regular  cut,  and  even  in  the 
