﻿Botany. 
  165 
  

  

  ence 
  that 
  the 
  faceted 
  stones 
  of 
  Copitz 
  near 
  Pirna, 
  are 
  of 
  glacial 
  

   origin. 
  I 
  give 
  the 
  results 
  of 
  some 
  of 
  my 
  own 
  explorations 
  among 
  

   the 
  ancient 
  bowlder 
  clays 
  of 
  Wetzikon, 
  and 
  other 
  localities. 
  I 
  point 
  

   out 
  that 
  the 
  Cambrian-scratched 
  stones 
  of 
  Norway 
  are 
  in 
  regions 
  

   that 
  are 
  still 
  under 
  the 
  influence 
  of 
  glacial 
  conditions 
  in 
  spite 
  of 
  

   the 
  mild 
  influences 
  of 
  the 
  gulf 
  stream. 
  I 
  then 
  give 
  a 
  sketch 
  of 
  

   the 
  distribution 
  of 
  bowlder-bearing 
  beds 
  in 
  India, 
  Australia 
  and 
  

   Africa, 
  but 
  have 
  no 
  evidence 
  from 
  personal 
  observation 
  to 
  offer 
  

   respecting 
  them. 
  I 
  admit 
  that 
  the 
  consensus 
  of 
  many 
  competent 
  

   observers 
  renders 
  it 
  difficult 
  to 
  believe 
  that 
  these 
  beds 
  do 
  not 
  

   exhibit 
  evidence 
  of 
  glacial 
  origin." 
  

  

  III. 
  Botany. 
  

  

  1. 
  Mechanism 
  of 
  the 
  movements 
  of 
  the 
  stamens 
  of 
  Berberis. 
  — 
  

   Chauveaud 
  (Comptes 
  rendus, 
  July 
  2), 
  suggests 
  a 
  new 
  explanation 
  

   of 
  the 
  curvature 
  of 
  the 
  filament 
  of 
  Barberry, 
  in 
  response 
  to 
  touch 
  

   or 
  other 
  irritation. 
  He 
  first 
  calls 
  attention 
  to 
  the 
  inadequacy 
  of 
  

   one 
  of 
  the 
  more 
  widely 
  accepted 
  explanations, 
  namely, 
  that 
  the 
  

   movement 
  is 
  in 
  consequence 
  of 
  the 
  expulsion 
  of 
  water, 
  showing 
  by 
  

   a 
  simple 
  experiment 
  that 
  water 
  does 
  not 
  escape 
  from 
  a 
  severed 
  fila- 
  

   ment. 
  He 
  says 
  that 
  if 
  a 
  stamen 
  be 
  cut 
  off 
  at 
  its 
  base, 
  and 
  held 
  in 
  

   a 
  dry 
  place, 
  it 
  is 
  possible, 
  after 
  it 
  has 
  recovered 
  and 
  straightened 
  

   itself, 
  to 
  excite 
  a 
  new 
  bending 
  and 
  after 
  a 
  second 
  straightening 
  

   to 
  cause 
  a 
  second 
  bending 
  ; 
  all 
  of 
  which 
  would 
  not 
  be 
  likely 
  to 
  

   take 
  place 
  if 
  there 
  was 
  at 
  each 
  movement 
  a 
  true 
  expulsion 
  of 
  

   water. 
  

  

  According 
  to 
  the 
  author, 
  the 
  following 
  is 
  the 
  anatomical 
  struc- 
  

   ture 
  of 
  the 
  filament 
  of 
  Berberis 
  aristata. 
  Besides 
  the 
  fibrovas- 
  

   cular 
  bundle 
  there 
  is 
  a 
  special 
  tissue 
  which 
  occupies 
  about 
  two- 
  

   thirds 
  of 
  the 
  transverse 
  section 
  and 
  about 
  two 
  thirds 
  of 
  the 
  length. 
  

   This 
  tissue 
  is 
  formed 
  of 
  narrow, 
  elongated 
  cells 
  which 
  are 
  packed 
  

   closely. 
  This 
  tissue 
  possesses, 
  especially 
  towards 
  the 
  extremities 
  

   of 
  the 
  cells, 
  minute 
  intercellular 
  spaces. 
  The 
  transverse 
  walls 
  of 
  

   its 
  cells 
  are 
  thin, 
  but 
  the 
  longitudinal 
  walls, 
  on 
  the 
  contrary, 
  

   are 
  thick, 
  with 
  thin 
  places 
  arranged 
  longitudinally. 
  This 
  elastic 
  

   tissue 
  is 
  covered 
  by 
  a 
  layer 
  which 
  is 
  practically 
  continuous 
  with 
  

   the 
  epidermis 
  on 
  the 
  internal 
  face 
  and 
  the 
  sides 
  of 
  the 
  filament 
  

   and 
  which 
  may 
  be 
  called 
  the 
  motile 
  tissue. 
  But 
  this 
  motile 
  layer 
  

   differs 
  from 
  the 
  rest 
  of 
  the 
  epidermis 
  in 
  many 
  ways. 
  Its 
  cells 
  are 
  

   rounded 
  and 
  thin-walled 
  on 
  their 
  outer 
  aspect, 
  but 
  notably 
  

   thicker 
  on 
  the 
  inner 
  or 
  deeper 
  aspect. 
  The 
  contents 
  differ 
  widely 
  

   from 
  those 
  of 
  the 
  other 
  epidermal 
  cells, 
  being 
  much 
  more 
  opaque. 
  

   At 
  the 
  bottom 
  of 
  each 
  cell 
  of 
  this 
  layer, 
  there 
  is, 
  when 
  the 
  organ 
  

   is 
  at 
  rest, 
  a 
  peculiar 
  thickening 
  of 
  the 
  protoplasm 
  into 
  a 
  sort 
  of 
  band. 
  

   Under 
  the 
  influence 
  of 
  irritation, 
  mechanical, 
  physical, 
  or 
  chemi- 
  

   cal, 
  the 
  protoplasm 
  reacts. 
  This 
  band 
  suddenly 
  stretches, 
  curves 
  

   into 
  a 
  bow, 
  and 
  while 
  its 
  ends 
  touch 
  and 
  draw 
  on 
  the 
  side 
  walls, 
  

   its 
  convexity 
  is 
  pressed 
  against 
  the 
  outer 
  wall, 
  resulting 
  in 
  a 
  

   shortening 
  and 
  thickening 
  of 
  the 
  cell. 
  This 
  causes 
  a 
  slight 
  but 
  

  

  