﻿Stability 
  and 
  Real 
  Atavism 
  159 
  

  

  respect 
  to 
  their 
  stability 
  by 
  different 
  writers 
  

   and 
  at 
  different 
  times. 
  In 
  doing 
  this 
  it 
  is 
  plain 
  

   that 
  it 
  is 
  very 
  essential 
  to 
  be 
  sure 
  of 
  the 
  purity 
  

   of 
  the 
  seed. 
  Specimens 
  must 
  be 
  grown 
  in 
  posi- 
  

   tions 
  isolated 
  from 
  their 
  allies, 
  and 
  if 
  possible 
  

   be 
  pollinated 
  artificially 
  with 
  the 
  exclusion 
  of 
  

   the 
  visits 
  of 
  insects. 
  This 
  may 
  be 
  done 
  in 
  differ- 
  

   ent 
  ways. 
  If 
  it 
  is 
  a 
  rare 
  species, 
  not 
  cultivated 
  

   in 
  the 
  neighborhood, 
  it 
  is 
  often 
  sufficient 
  to 
  make 
  

   sure 
  of 
  this 
  fact. 
  Pollen 
  may 
  be 
  conveyed 
  by 
  

   bees 
  from 
  distances 
  of 
  some 
  ten 
  or 
  twenty 
  

   meters, 
  or 
  in 
  rare 
  cases 
  from 
  some 
  hundred 
  

   meters 
  and 
  more, 
  but 
  a 
  greater 
  distance 
  is 
  or- 
  

   dinarily 
  sufficient 
  for 
  isolation. 
  If 
  the 
  flowers 
  

   fertilize 
  themselves, 
  as 
  is 
  more 
  often 
  the 
  case 
  

   than 
  is 
  generally 
  supposed, 
  or 
  if 
  it 
  is 
  easy 
  to 
  

   pollinate 
  them 
  artificially, 
  with 
  their 
  own 
  pollen 
  

   or 
  in 
  small 
  groups 
  of 
  similar 
  individuals, 
  the 
  

   best 
  way 
  is 
  to 
  isolate 
  them 
  by 
  means 
  of 
  close 
  

   coverings. 
  When 
  flowering, 
  the 
  plants 
  are 
  as 
  a 
  

   rule 
  too 
  large 
  to 
  be 
  put 
  under 
  bell-glasses, 
  and 
  

   moreover 
  such 
  coverings 
  would 
  keep 
  the 
  air 
  

   moist, 
  and 
  cause 
  the 
  flower-buds 
  to 
  be 
  thrown 
  

   off. 
  The 
  best 
  coverings 
  are 
  of 
  netting, 
  or 
  of 
  

   canvas 
  of 
  sufficiently 
  wide 
  mesh, 
  although 
  after 
  

   a 
  long 
  experience 
  I 
  greatly 
  prefer 
  cages 
  of 
  

   fine 
  iron-wire, 
  which 
  are 
  put 
  around 
  and 
  over 
  

   the 
  whole 
  plant 
  or 
  group 
  of 
  plants, 
  and 
  fastened 
  

   securely 
  and 
  tightly 
  to 
  the 
  ground. 
  

  

  