174  The  Apocynacece  in  Materia  Medica.  {^il™^^™' 
Allamanda  Cathartica  L.,  all  the  Allamanda  are  energetic 
evacuants.  The  A.  cathartica  is  a  native  of  Guiana,  where  the 
leaves  are  commonly  employed  as  a  purgative.  The  A.  Schottii 
Pohl.  of  Brazil  has  similar  properties. 
Echites  suberecta  Jacq. — A  plant  of  the  West  Indies,  especially 
Jamaica,  and  introduced  into  the  Bahamas.  Bowrey  has  analyzed 
the  plant  and  isolated  Urechitine  a  very  toxic,  crystalline  glucoside ; 
Urechitoxine,  likewise  a  toxic  glucoside,  acrid  and  crystalline  or 
amorphous.  These  two  bodies  are  extremely  active  cardiac  poisons 
and  their  therapeutic  application  does  not  appear  permissible.  The 
plant  is  stated  to  be  used  for  criminal  poisonings  by  the  negroes. 
The  leaves  of  the  Echites  biflora  Jacq.  of  Central  America  and  the 
Antilles  is  stated  to  be  purgative  and  applied  topically  to  scrofulous 
ulcers.  The  leaves  of  Echites  longiflora  Desf,  of  the  Argentine 
Republic  are  strongly  purgative  and  in  infusion  are  employed  against 
haemorrhoids  and  used  also  in  cataplasm. 
Aspidosperma  Quebracho  Schlecht. — The  leaves  of  this  tree  are 
verticillate  in  threes,  deep  green,  lanceolate,  subsessile,  coriaceous, 
smooth  and  terminated  as  in  many  of  the  species  of  this  genus  by 
a  sharp  point.  They  are  said  to  contain  27.5  per  cent,  of  tannin 
and  to  be  employed  in  the  industries. 
Geissospermum  Vellosii  Fr.  Allem. — The  leaves  of  this  plant 
are  extremely  bitter.  They  contain  Pereirine,  but  in  less  quantity 
than  the  bark  and  seem  to  be  but  little  used.  They  are  lanceolate, 
attenuated  at  the  base  and  short  petiolate  and  prolonged  into  a  long 
point  at  the  summit ;  borders  undulate,  entire ;  the  surface  smooth 
and  shining  ;  greenish  or  brownish,  brighter  but  less  glossy  beneath. 
CAOUTCHOUCS  AND  GUTTAS. 
The  products  formed  by  coagulation  of  the  latex  of  the  apocynaceae 
nearly  all  caoutchoucs,  but  some  are  true  guttas*  The  number  of 
apocynacese  containing  caoutchouc  is  considerable,  but  only  in  com- 
*  Caoutchouc  and  Gutta  Percha  are  two  substances  very  similar,  differing 
only  in  a  few  points.  At  the  ordinary  temperature  Caoutchouc  is  elastic,  Gutta 
is  solid.  On  warming,  the  caoutchouc  becomes  adhesive,  but  remains  elastic  ; 
the  gutta  becomes  malleable  and  plastic,  but  not  elastic.  With  prolonged 
action  of  heat  and  air  caoutchouc  is  transformed  to  a  sort  of  pitch,  gutta 
becomes  brittle  and  resinous.  Ether  readily  dissolves  caoutchouc,  and  is 
a  poor  solvent  for  gutta  ;  with  oil  of  turpentine  the  solvent  action  is  reversed. 
Sulphur  combines  readily  with  caoutchouc  and  but  poorly  with  gutta. 
