﻿Dr. 
  L. 
  Plate 
  on 
  Noctiluca 
  miliaria, 
  Sur. 
  27 
  

  

  If 
  Noctilucm 
  be 
  laid 
  upon 
  moist 
  blotting-paper 
  and 
  exam- 
  

   ined 
  under 
  a 
  high 
  power 
  the 
  light 
  radiating 
  from 
  them 
  may- 
  

   be 
  classed 
  under 
  four 
  categories 
  : 
  — 
  

  

  1. 
  Lightning-like, 
  intense 
  luminosity 
  of 
  the 
  whole 
  outer 
  

   layer, 
  immediately 
  followed 
  by 
  darkness 
  ; 
  

  

  2. 
  The 
  same, 
  but 
  with 
  a 
  faint 
  after- 
  luminosity 
  persisting 
  

   for 
  one 
  or 
  two 
  minutes 
  ; 
  

  

  3. 
  Dull 
  luminosity 
  of 
  the 
  outer 
  zone 
  of 
  plasma 
  or 
  of 
  some 
  

   considerable 
  portions 
  of 
  it, 
  with 
  at 
  the 
  same 
  time 
  strong 
  

   sparkling 
  of 
  particular 
  small 
  points 
  ; 
  

  

  4. 
  A 
  great 
  portion 
  of 
  the 
  surface 
  is 
  entirely 
  or 
  partially 
  

   luminous, 
  the 
  luminosity 
  being 
  composed 
  of 
  numerous 
  small 
  

   points. 
  

  

  If 
  we 
  consider 
  the 
  results 
  at 
  which 
  Radziszewski 
  * 
  has 
  

   arrived 
  it 
  would 
  seem 
  probable 
  that 
  the 
  diffused 
  light 
  of 
  the 
  

   surface 
  of 
  the 
  body 
  proceeds 
  from 
  the 
  smallest 
  fat-drops 
  of 
  

   the 
  fine-meshed 
  plasmatic 
  net 
  which 
  occurs 
  throughout 
  

   immediately 
  beneath 
  the 
  cuticle, 
  while 
  the 
  light 
  consisting 
  of 
  

   separate 
  points 
  owes 
  its 
  origin 
  to 
  the 
  coarser 
  fat-drops 
  of 
  the 
  

   peripheral 
  network 
  of 
  sarcode. 
  

  

  The 
  question 
  whether 
  the 
  phosphorescence 
  of 
  Noctiluca 
  is 
  

   or 
  is 
  not 
  a 
  phenomenon 
  subject 
  to 
  the 
  will 
  of 
  the 
  animal 
  has 
  

   hitherto 
  been 
  but 
  little 
  discussed. 
  I 
  agree 
  with 
  Pouchet 
  f, 
  

   who 
  says 
  of 
  the 
  luminosity 
  of 
  the 
  Cilioflagellata 
  that 
  " 
  it 
  is 
  

   a 
  simple 
  physico-chemical 
  property, 
  which 
  appears 
  in 
  the 
  

   inferior 
  creatures 
  to 
  be 
  independent 
  of 
  the 
  reciprocal 
  vital 
  

   manifestations 
  of 
  the 
  individuals; 
  " 
  and 
  I 
  therefore 
  regard 
  the 
  

   luminosity 
  of 
  Noctiluca 
  as 
  an 
  involuntary 
  act, 
  induced 
  by 
  

   exterior 
  irritation, 
  and 
  from 
  which 
  the 
  animal 
  cannot 
  escape. 
  

   Thus, 
  if 
  we 
  observe 
  lively 
  Noctiluca? 
  which 
  are 
  in 
  a 
  perfectly 
  

   quiet 
  place, 
  we 
  find 
  that 
  there 
  is 
  a 
  complete 
  disappearance 
  of 
  

   the 
  light. 
  That 
  traces 
  of 
  it 
  now 
  and 
  then 
  recur 
  is 
  probably 
  

   due 
  to 
  the 
  fact 
  that 
  the 
  Noctiluca? 
  collected 
  into 
  a 
  dense 
  layer 
  at 
  

   the 
  surface 
  of 
  the 
  water 
  sometimes 
  disturb 
  one 
  another, 
  or 
  are 
  

   sometimes 
  irritated 
  by 
  Entomostraca 
  and 
  other 
  small 
  animals, 
  

   the 
  presence 
  of 
  which 
  cannot 
  be 
  prevented, 
  and 
  are 
  thus 
  

   brought 
  to 
  luminosity. 
  On 
  the 
  other 
  hand, 
  the 
  phenomenon 
  

   follows 
  immediately 
  and 
  without 
  exception 
  upon 
  any 
  intense 
  

   irritation, 
  like 
  thunder 
  after 
  lightning. 
  

  

  Whether 
  and 
  how 
  far 
  the 
  luminosity 
  of 
  the 
  sea, 
  which 
  owes 
  

   its 
  origin 
  to 
  the 
  cooperation 
  of 
  thousands 
  upon 
  thousands 
  of 
  

   minute 
  organisms, 
  depends 
  upon 
  the 
  existing 
  conditions 
  of 
  

   the 
  weather, 
  has, 
  so 
  far 
  as 
  I 
  know, 
  been 
  hitherto 
  but 
  little 
  

   tested. 
  I 
  therefore, 
  during 
  six 
  weeks 
  on 
  the 
  island 
  of 
  Bor- 
  

  

  * 
  Liebig's 
  Ann. 
  der 
  Cheniie, 
  Bd. 
  cciii. 
  (1880), 
  p. 
  305. 
  

   t 
  Journ. 
  Anat. 
  Physiol, 
  tome 
  xix. 
  (1883), 
  p. 
  437. 
  

  

  