VARIETIES. 
469 
The  concrete  milky  juice  of  the  Cryptostigeia  grandifiora — a  handsome 
climber,  common  in  the  Madras  Peninsula — has  long  been  known  to  con- 
tain caoutchouc,  but  it  has  not  yet  been  collected  for  the  purposes  of  com- 
merce, and  it  is  doubtful  if  a  sufficient  quantity  could  be  obtained  to  render 
it  an  article  of  trade.  The  milk  from  the  cow  tree  appears  to  contain 
caoutchouc.  It  is  supposed  to  be  obtained  from  Taherncemontana  utilis  of 
Arnofc,  or  a  species  of  Brosimum.  On  the  river  Demarara  the  Indians 
climb  the  rubber  tree,  tap  the  trunk,  and  as  the  gum  exudes,  rub  it  on  their 
bodies  till  it  assumes  a  sufficient  consistency  to  be  formed  into  balls. 
Recent  inquiry  has  shown  that  caoutchouc  is  furnished  of  good  quality, 
by  a  large  number  of  milky-juiced  plants  belonging  to  different  families 
(Sapotacea,  Apocynacece  and  Euphorbiaceoe).  In  the  East,  Assam  now 
furnishes  large  quantities  of  india-rubber  from  Ficus  elastica.  Complaints 
are,  however,  made  of  the  want  of  care  in  the  preparation  of  the  article 
from  Assam. 
If  the  previous  purifying  of  the  gum  be  properly  attended  to — and  in 
this  process  the  whole  art  of  manufacturing  the  perfectly  elastic  gum  of 
commerce  seems  to  exist — the  gum  should  not,  by  any  exposure  to  the  at- 
mosphere, be  subject  to  the  least  degree  of  clamminess  or  viscidity;  and 
if  this  important  point  be  not  fully  attained,  the  article  is  of  no  use  in  the 
manufacture  of  those  fine  elastic  threads  which  constitute  its  chief  value 
in  the  European  markets.  The  art  of  obtaining  this  complete  freedom 
from  clamminess,  and  consequent  perfect  elasticity,  does  not  appear  by 
any  means  to  have  been  reduced  to  a  certainty;  and,  consequently,  a  far 
better  acquaintance  with  the  article  than  is  yet  possessed  by  the  Assam 
manufacturers  seems  requisite  before  it  can  be  obtained  with  constantly 
the  same  results. 
A  substance  resembling  caoutchouc  was  said  to  have  been  obtained  in 
Sierra  Leone  from  a  plant  of  the  Euphorbia  tribe,  so  long  ago  as  Tuckey's 
voyage  up  the  Congo,  in  1816.  Some  large  forest  trees,  belonging  to  the 
Sapotaceee  family,  which  abound  at  the  foot  of  the  Ghauts,  N.  E.  of  Trevan- 
drum,  furnish  a  valuable  elastic  gum,  called  by  the  Malays  pauchouthee. 
which  bears  a  strong  resemblance  to  gutta  percha  both  in  external  appear- 
ance and  mechanical  properties,  and  the  real  Isonandra  gutta,  would  appear 
to  be  common  in  the  forests  of  the  Neilgherries. 
Gutta  Percha  has  been  discovered  in  the  British  province  of  Mergui, 
and  though  not  precisely  identical  with  the  gutta  percha  of  commerce,  it 
possesses  all  the  valuable  properties  of  that  substance,  including  plasticity 
in  hot  water,  and  the  power  of  insulating  electric  currents. 
The  tree  from  which  the  true  gutta  taban  is  produced  (erroneously  mis- 
named in  Europe  gutta  percha,  a  gum  yielded  by  a  different  tree),  is  one 
of  the  most  common  in  the  jungles  of  Johore  and  the  Malay  Peninsula. 
It  is  not  found  in  the  alluvial  districts,  but  in  undulating  or  hilly  ground. 
There  is  a  great  uniformity  in  the  size  of  the  full  grown  tabans,  which  rise 
with  perfectly  straight  trunks  from  60  to  80  feet  in  height,  and  from  2  to  3 
