India  Rubber — Collection  in  Mexico,  Varieties,  etc. — Sir  Henry  Dering,
in  a  report  on  the  productions  of  Mexico,  says  the  rubber  tree  is  indige-
nous to  Mexico  and  is  found  growing  wild  along  both  coasts,  below  22
degrees  north  latitude,  from  sea  level  to  altitudes  running  from  1,200  to
1,500  feet,  and  principally  by  the  river  meadows.  Rubber  is  essentially  a
tropical  tree,  hence  it  requires  a  hot  and  moist  climate.  The  temperature
best  adapted  for  its  vigorous  growth  is  above  86"*  Fahrenheit,  and  the  rain-
fall should  be  at  least  60  to  70  inches  per  annum.  There  are  eight  kinds
of  rubber  trees  that  grow  wild  in  the  country,  but  the  kind  known  under
the  name  of  "  Castilloa  elastica  "  is  the  most  important  and  the  best,  as  it
is  very  much  sought  for,  for  its  sap  and  for  propagation.  Regarding  the
work  of  extracting  the  rubber,  one  man  will  tap  from  twenty  to  twenty-
five  trees  a  day  if  the  operation  is  performed  carefully  and  methodically.
In  most  places  the  tapping  is  done  in  May  and  sometimes  again  in  Oc-
tober, but  it  is  not  advisable  to  repeat  the  operation  as  often  as  that.  The
process  generally  consists  in  making  two  or  three  incisions  in  the  lower
part  of  the  tree  and  collecting  the  sap  that  flows  from  them  on  clay  vessels
placed  next  to  the  trunk.  The  process  can  be  repeated  every  year  for
twenty-five  years  or  more,  especially  if  the  wound  is  covered  with  wax  or
clay  after  the  flow  of  the  sap  has  ceased.  When  there  is  a  large  quantity
of  milk  gathered  it  is  placed  in  a  barrel  having  a  faucet  and  a  solution
of  five  ounces  of  sodium  chloride  or  carbonate  in  sufficient  water  to


BASSIA   LONGIFOLIA.
