﻿652 
  Mutations 
  

  

  nodes 
  may 
  adjust 
  themselves 
  to 
  the 
  forces 
  which 
  

   tend 
  to 
  cause 
  their 
  expansion 
  is 
  by 
  straighten- 
  

   ing 
  the 
  rope. 
  In 
  doing 
  so 
  they 
  may 
  find 
  the 
  re- 
  

   quired 
  space, 
  by 
  growing 
  out 
  in 
  an 
  unusual 
  

   direction, 
  bending 
  their 
  axes 
  and 
  twisting 
  the 
  

   ribs. 
  

  

  To 
  prove 
  the 
  validity 
  of 
  this 
  explanation, 
  a 
  

   simple 
  experiment 
  may 
  be 
  given. 
  If 
  the 
  fibro- 
  

   vascular 
  rope 
  is 
  the 
  mechanical 
  impediment 
  

   which 
  hinders 
  the 
  normal 
  growth, 
  we 
  may 
  try 
  

   the 
  effect 
  of 
  cutting 
  through 
  this 
  rope. 
  By 
  this 
  

   means 
  the 
  hindrance 
  may 
  at 
  least 
  locally 
  

   be 
  removed. 
  Now, 
  of 
  course, 
  the 
  operation 
  

   must 
  be 
  made 
  in 
  an 
  early 
  stage 
  before, 
  

   or 
  at 
  the 
  beginning 
  of 
  the 
  period 
  of 
  growth, 
  

   in 
  every 
  case 
  before 
  the 
  uncurling 
  of 
  the 
  

   rope 
  begins. 
  Wounds 
  made 
  at 
  this 
  time 
  are 
  apt 
  

   to 
  give 
  rise 
  to 
  malformations, 
  but 
  notwithstand- 
  

   ing 
  this 
  difficulty 
  I 
  have 
  succeeded 
  in 
  giving 
  the 
  

   necessary 
  proof. 
  Stems 
  operated 
  upon 
  become 
  

   straight 
  where 
  the 
  rope 
  is 
  cut 
  through, 
  though 
  

   above 
  and 
  under 
  the 
  wounded 
  part 
  they 
  go 
  on 
  

   twisting 
  in 
  the 
  usual 
  way. 
  

  

  Sometimes 
  the 
  plants 
  themselves 
  succeed 
  in 
  

   tearing 
  the 
  rope 
  asunder, 
  and 
  long 
  straight 
  in- 
  

   ternodes 
  divide 
  the 
  twisted 
  stems 
  in 
  two 
  or 
  more 
  

   parts 
  in 
  a 
  very 
  striking 
  manner. 
  A 
  line 
  of 
  torn 
  

   leaf-bases 
  connects 
  the 
  two 
  parts 
  of 
  the 
  screw 
  

   and 
  gives 
  testimony 
  of 
  what 
  has 
  passed 
  within 
  

  

  