294 
Breeding  Medicinal  Plants. 
A.m.  Jour.  Pharm. 
July,  1913. 
The  selected  plants  so  far  tested  indicate  a  variation  in  yield  of 
from  0.55  per  cent,  to  0.87  per  cent,  of  alkaloids.  The  progeny  of 
these  plants  of  known  yield  will  be  tested  in  a  similar  manner. 
The  external  characters  of  the  belladonna  plant  are  extremely 
uniform,  with  the  exception  of  total  yield  of  leaves  and  roots  per 
plant.  This  exception  will  be  taken  advantage  of  in  selecting  for 
increased  production  of  these  products.  Individuals  vary  in  amount 
Fig.  i. 
Commercial  test  plot  of  Belladonna. 
of  dry  root  produced  from  139  grams  to  203  grams.  It  has  been 
stated  that  the  percentage  of  alkaloids  in  the  roots  of  this  plant 
increase  markedly  after  the  first  year,  and  reach  a  maximum  at 
the  end  of  the  third  year's  growth.  Belladonna  is  not  perfectly 
hardy  throughout  the  central  United  States,  and  more  hardy 
strains  must  be  developed  before  the  above  condition  can  be  ob- 
served to  advantage.    Sixteen  hundred  plants  are  now  being  tested 
