6 
London  Botanic  Gardens. 
(  Am.  Jour.  Pharni. 
X     January,  1900. 
The  most  important  medicinal  plants  in  the  Succulent  House  are  the 
numerous  species  of  Aloe  from  which  aloes  is  obtained  ;  among  these  may  be 
mentioned  Aloe  Perryi,  Baker,  one  of  the  plants  from  which  Socotrine  aloes 
is  known  to  be  derived,  A.  ferox,  Mill.,  which  yields  a  part,  at  least,  of  Cape 
aloes,  and  A.  Chinensis,  Baker,  to  which  Barbados  or  Curacoa  aloes  has  been 
referred  ;  other  species  are  doubtless  used  for  the  production  of  aloes,  but 
nothing  very  definite  is  known  on  the  subject.  Other  plants  of  interest  in  this 
collection  are:  Cereus  grandiflorus,  Mill.,  whose  flowers  are  known  in  com- 
merce as  "Cactus  Grandiflorus";  Euphorbia  resinifera,  Berg.,  the  source  of 
Buphorbium  ;  Nopalea  coccinellifera,  Salm-Dyck  {Opuntia  cochinillifera, 
Mill.),  which,  together  with  other  species  of  the  same  genus,  serve  as  food  for 
the  cochineal  insect ;  and  Xanlhorrhcea  hastilis,  R.  Br.,  the  source  of  the  resin 
known  in  commerce  as  grasstree  gum  or  gum  acroides. 
The  two  Economic  houses  lorm  part  of  a  "  range  "  constructed  in  the 
form  of  a  T  (see  Plate  X).  The  heating  of  this  range  is  so  devised 
that  the  highest  temperature  is  attained  near  the  junction  of  the  bars 
of  the  "  T,"  the  houses  becoming  cooler  towards  the  extremities.  This 
"  New  Range,"  as  it  is  called,  was  erected  in  1869,  shortly  after  the 
opening  of  the  "  Kew  Gardens  "  railroad  station.  The  Director's  report 
to  Parliament  for  1881  contains  a  list  of  the  economic  plants  grow- 
ing at  Kew  at  that  time,  and,  in  connection  with  this  list,  the 
Director  stated  that  when  the  Economic  houses  were  built  "  some 
of  the  most  conspicuous  and  now  widely  spread  and  even  commer- 
cially important  of  the  plants  for  which  they  were  intended,  were 
absolutely  unknown  in  Europe,  or  known  only  as  botanical  curiosi- 
ties of  no  known  use  to  mankind  ;  such  are  some  of  the  cinchonas, 
of  the  American  and  African  rubbers,  the  Liberian  coffee,  etc."  In 
1899  these  houses  were  rebuilt  as  they  exist  at  present.  It  had  been 
one  of  Sir  William  Hooker's  main  objects,  from  the  first,  to  pay 
special  attention  to  the  study  and  cultivation  of  economic  plants, 
including  such  as  are  used  in  medicine,  but  it  was  not  until  1865 
that  any  attempt  was  made  to  bring  them  together,  when  an  old 
house,  known  as  the  "  Victoria  House,"  was  set  aside  by  Sir  Joseph 
Hooker  for  the  purpose.  On  the  completion  of  the  new  range  this 
old  Victoria  House  was  demolished. 
The  following  is  a  list  of  the  medicinal  plants  growing  in  the 
Economic  houses  when  I  last  visited  them  : 
In  the  tropical  house: — Abrus  precatorius,  L,.,  from  which  are  obtained  the 
poisonous  Jequirity  seeds  used  in  ophthalmic  practice  ;  Acacia  Catechu,  Willd., 
the  source  of  Black  Catechu  or  Cutch  ;  CEgle  Marmelos,  Correa,  whose  fruit 
is  used  in  India  for  the  treatment  of  dysentery  ;  Anamirta  Cocculus,  Wight  et 
