﻿[74] 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION., 
  

  

  ganglia 
  themselves 
  by 
  cutting 
  them 
  apart 
  in 
  a 
  longitudinal 
  as 
  well 
  as 
  transverse 
  di- 
  

   rection. 
  These 
  lesions 
  produced 
  phenomena 
  which 
  were 
  quite 
  varied, 
  and 
  which 
  suc- 
  

   ceeded, 
  from 
  moment 
  to 
  moment, 
  in 
  an 
  order 
  more 
  or 
  less 
  determinate. 
  A 
  longitudi- 
  

   nal 
  section, 
  dividing 
  unequally 
  the 
  subcesoimageal 
  ganglion, 
  gave 
  rise 
  to 
  some 
  lateral 
  

   movements; 
  the 
  insect 
  turned 
  as 
  if 
  rearing 
  up 
  like 
  a 
  horse 
  (en 
  manege), 
  at 
  first 
  mo- 
  

   mentarily 
  from 
  the 
  side 
  of 
  the 
  wound, 
  then 
  definitely 
  from 
  the 
  opposite 
  side 
  ; 
  it 
  fell 
  

   over 
  on 
  its 
  back 
  from 
  the 
  side 
  opposite 
  the 
  wound, 
  and, 
  in 
  rising, 
  made 
  a 
  complete 
  

   revolution. 
  It 
  lost 
  the 
  power 
  of 
  leaping. 
  The 
  transverse 
  section 
  of 
  the 
  same 
  ganglion 
  

   produced 
  some 
  accidents 
  much 
  more 
  grave. 
  The 
  cricket 
  raised 
  the 
  right 
  foot, 
  as 
  if 
  to 
  

   find 
  a 
  point 
  of 
  support, 
  and 
  tumbled 
  over 
  often 
  to 
  the 
  left 
  ; 
  while 
  on 
  the 
  other 
  side 
  

   we 
  could 
  not 
  succeed 
  in 
  reversing 
  it. 
  The 
  reflex 
  actions 
  were 
  sufficiently 
  pronounced. 
  

  

  The 
  section 
  of 
  a 
  single 
  cord 
  of 
  the 
  chain 
  does 
  not 
  produce 
  cross 
  effects. 
  It 
  intro- 
  

   duces 
  a 
  disturbance 
  in 
  the 
  equilibrium 
  of 
  the 
  functions 
  of 
  relation 
  of 
  the 
  two 
  sides 
  of 
  

   the 
  body, 
  and 
  is 
  always 
  indicated 
  by 
  the 
  insect's 
  walking 
  in 
  a 
  circle, 
  the 
  feet 
  on 
  on< 
  

   Bide 
  functioning 
  more 
  rapidly 
  than 
  those 
  on 
  the 
  other, 
  &c. 
  

  

  In 
  combining 
  the 
  different 
  sections 
  which 
  precede, 
  or 
  in 
  cutting 
  simultaneously 
  the 
  

   two 
  cords 
  on 
  a 
  point 
  of 
  their 
  tract, 
  and 
  a 
  single 
  one 
  between 
  them 
  on 
  some 
  other 
  

   point, 
  we 
  obtain 
  some 
  complementary 
  information 
  as 
  to 
  the 
  mode 
  of 
  transmission 
  o, 
  

   nervous 
  actions. 
  

  

  The 
  result 
  of 
  these 
  experiments 
  establishes 
  the 
  fact 
  that 
  the 
  transmission 
  of 
  the 
  will 
  

   is 
  always 
  made 
  directly, 
  and 
  without 
  a 
  transverse 
  effect, 
  while 
  the 
  reflex 
  actions, 
  

   although 
  they 
  are 
  transmitted 
  more 
  easily 
  by 
  a 
  direct 
  course, 
  take 
  place, 
  though 
  

   with 
  less 
  intensity, 
  by 
  a 
  transverse 
  effect. 
  Another 
  general 
  fact 
  that 
  Yersin 
  has 
  in- 
  

   ferred 
  from 
  his 
  experiments 
  is 
  that 
  the 
  maximum 
  of 
  intensity 
  of 
  the 
  movements 
  which 
  

   he 
  has 
  observed 
  after 
  the 
  operation 
  has 
  always 
  occurred 
  on 
  the 
  side 
  on 
  which 
  the 
  opera- 
  

   tion 
  was 
  made. 
  This 
  is 
  why 
  in 
  its 
  rearing 
  gait 
  (marclie 
  en 
  manege) 
  the 
  insect 
  turns 
  in 
  

   a 
  circle 
  from 
  the 
  opposite 
  side. 
  So 
  when 
  we 
  make 
  the 
  section 
  of 
  the 
  right 
  cord 
  be- 
  

   tween 
  the 
  head 
  and 
  thorax, 
  the 
  animal 
  begins 
  at 
  first 
  to 
  turn 
  to 
  the 
  right, 
  but 
  at 
  the 
  

   end 
  of 
  a 
  moment 
  it 
  changes 
  and 
  turns 
  to 
  the 
  left. 
  It 
  is, 
  indeed, 
  immediately 
  after 
  the 
  

   section 
  of 
  the 
  right 
  cord 
  that 
  the 
  right 
  feet 
  cease 
  to 
  be 
  submitted 
  to 
  the 
  action 
  of 
  the 
  

   will, 
  while 
  those 
  of 
  the 
  left 
  side 
  continue 
  to 
  obey 
  the 
  will, 
  acting 
  with 
  more 
  activity, 
  

   and 
  thus 
  causing 
  the 
  insect 
  to 
  turn 
  to 
  the 
  right. 
  But 
  at 
  the 
  end 
  of 
  an 
  instant, 
  the 
  re- 
  

   flex 
  action 
  setting 
  in 
  motion 
  the 
  right 
  feet, 
  this 
  impresses 
  upon 
  them 
  a 
  more 
  lively 
  

   movement 
  than 
  to 
  the 
  left 
  feet, 
  which 
  act 
  under 
  the 
  direct 
  impulse 
  of 
  the 
  will, 
  and 
  

   they 
  consequently 
  turn 
  the 
  insect 
  to 
  the 
  left. 
  For 
  the 
  same 
  reason, 
  the 
  insect 
  

   placed 
  on 
  its 
  back 
  will 
  recover 
  itself 
  on 
  the 
  wounded 
  side. 
  

  

  As 
  the 
  result 
  of 
  later 
  experiments, 
  read 
  before 
  the 
  Socie'te' 
  Helve"tique 
  des 
  Sciences 
  

   Naturelles, 
  at 
  Lausanne, 
  in 
  1861, 
  Yersin 
  stated 
  that 
  each 
  ganglion 
  can 
  become 
  the 
  

   point 
  of 
  departure 
  of 
  spontaneous 
  movements 
  and 
  a 
  center 
  of 
  distinct 
  perceptions. 
  

  

  The 
  following 
  is 
  an 
  abstract 
  of 
  his 
  memoir 
  to 
  the 
  French 
  Academy, 
  the 
  observations 
  

   having 
  been 
  made 
  in 
  1856, 
  and 
  relating 
  to 
  the 
  effects 
  of 
  the 
  section 
  of 
  the 
  cords 
  or 
  

   commissures 
  connecting 
  the 
  ganglions 
  of 
  the 
  nervous 
  cord 
  : 
  

  

  1. 
  The 
  co-ordination 
  of 
  movements 
  is 
  not 
  disturbed 
  by 
  the 
  section 
  of 
  two 
  cords 
  at 
  a 
  

   time 
  at 
  any 
  point 
  whatsoever 
  of 
  the 
  chain. 
  

  

  2. 
  On 
  the 
  contrary, 
  locomotion 
  becomes 
  abnormal, 
  (1) 
  every 
  time 
  we 
  cut 
  a 
  single 
  

   cord 
  at 
  a 
  point 
  from 
  the 
  anterior 
  chain 
  to 
  the 
  ganglion 
  of 
  the 
  metathorax 
  ; 
  (2) 
  every 
  

   time 
  we 
  make 
  two 
  or 
  several 
  sections, 
  each 
  on 
  a 
  single 
  cord, 
  between 
  different 
  gan- 
  

   glia, 
  one 
  at 
  least 
  of 
  the 
  sections 
  being 
  situated 
  on 
  a 
  point 
  anterior 
  to 
  the 
  metathorax. 
  

  

  3. 
  In 
  the 
  vertebrate 
  animals 
  the 
  nerves 
  properly 
  so 
  called 
  have 
  all 
  their 
  roots 
  in 
  

   the 
  elongated 
  medulla 
  and 
  in 
  the 
  spinal 
  marrow. 
  In 
  the 
  articulates 
  almost 
  all 
  the 
  

   nerves 
  arise 
  from 
  the 
  ganglia. 
  Anatomical 
  analogy 
  leads 
  us 
  to 
  compare 
  the 
  ganglia 
  

   of 
  thf 
  chain 
  to 
  a 
  marrow. 
  

  

  4. 
  The 
  experiments 
  here 
  given 
  in 
  resume" 
  seem 
  to 
  us 
  to 
  establish 
  the 
  fact 
  that 
  it 
  is 
  

   the 
  ensemble 
  of 
  the 
  cephalic 
  and 
  thoracic 
  ganglia 
  which 
  preside 
  over 
  the 
  co-ordination 
  

   of 
  locomotive 
  movements 
  without 
  its 
  being 
  possible 
  to 
  ascertain 
  whether 
  this 
  function 
  

   resides 
  in 
  one 
  of 
  these 
  organs 
  to 
  the 
  exclusion 
  of 
  the 
  others. 
  Thus 
  this 
  marrow 
  rep- 
  

   resents 
  at 
  the 
  same 
  time 
  the 
  cerebellum 
  of 
  the 
  higher 
  animals. 
  

  

  5. 
  It 
  is 
  very 
  probable 
  that 
  it 
  is 
  therefore 
  in 
  the 
  reunion 
  of 
  the 
  ganglia 
  that 
  we 
  

   should 
  seek 
  the 
  analogy 
  of 
  the 
  brain 
  of 
  vertebrates. 
  

  

  