Am.  Jour.  Pharm. 
June,  1894. 
Economic  Botany. 
291 
rabi,  the  cow  or  Jersey  cabbage,  and  as  some  believe,  the  com- 
mon turnip,  forms  in  appearance  and  habit  often  so  different  from 
each  other,  that  no  one  not  a  botanist  would  suspect  their  common 
origin.  Precisely  how  they  originated  we  don't  know ;  but  they 
are  the  result  of  a  long  course  of  cultivation.  Are  there  no  other 
of  our  Cruciferae  that  possess  similar  possibilities  ? 
A  few  years  ago  there  were  enumerated  in  the  transactions  of  one 
of  the  horticultural  societies  of  Great  Britain,  1,500  different  vari- 
eties of  the  apple,  and  this  probably  does  not  include  nearly  all  that 
have  been  produced  from  the  original  wild  apple  of  Europe  and 
Asia.  Many  other  species  of  Pyrus  that  have  never  been  subjected 
to  experiment,  possess,  for  aught  we  know,  as  much  promise  as 
Pyrus  Malus. 
The  Japanese  have  made  out  of  their  persimmon  what  they 
regard  as  their  most  valuable  cultivated  fruit,  but  the  wild  plant,  I 
am  told,  yields  a  fruit  no  more  desirable  than  those  of  our  two  wild 
species.  In  fact,  our  common  persimmon  shows  a  great  tendency 
to  variation,  even  in  the  wild  state,  thus  making  it  a  most  promising 
subject  for  experiment.  Scarcely  less  urgently  do  the  Butternut, 
Black  Walnut,  Hickories,  Hazels,  Blueberries,  Serviceberry,  some 
of  the  Shepherdias,  the  species  of  Physalis,  Apios  tuberosa,  Psora- 
lia  esculenta  and  many  other  native  species,  invite  us  to  experiment. 
Of  course,  experiments  of  this  kind  must  be  made  by  govern- 
ment and  in  long  lines  of  policy,  as  important  results  in  the  case  of 
long-lived  plants  at  least  could  not  be  expected  in  a  single  genera- 
tion of  men.  It  is  not  necessary  to  suppose,  however,,  that  because 
it  has  taken  thousands  of  years  to  bring  about  the  present  excel- 
lence of  many  of  our  food  plants,  it  would  take  the  same  length  of 
time  to  similarly  improve  our  wild  ones.  What  was  accomplished 
unintelligently  in  long  ages  might  probably  be  done  in  a  few  genera- 
tions by  taking  advantage  of  the  now  known  laws  of  variation, 
hybridizing  and  artificial  selection. 
Coming  again  to  medicinal  plants,  I  find  that  the  last  edition  of 
the  U.  S.  Dispensatory  enumerates  over  1,300  that  are  more  or  less 
employed  in  medicine,  and  a  fair  estimate  of  the  whole  number  in 
use,  I  think,  would  be  not  far  from  3,000.  This,  of  course,  would 
not  include  all  that  have  been  employed  in  medicine ;  it  would  be 
impossible,  even  approximately,  to  estimate  these ;  but  only  those 
plants  that  are  at  the  present  time  more  or  less  habitually  employed 
