﻿336 
  On 
  Parasitic 
  Castration 
  in 
  Lumbricus 
  lierculeus. 
  

  

  Microscopical 
  examination 
  showed 
  that 
  the 
  cause 
  of 
  the 
  

   abnormality 
  lay 
  in 
  a 
  bacterial 
  infection, 
  not 
  only 
  the 
  cyto- 
  

   phores 
  but 
  the 
  spermatocytes 
  themselves 
  being 
  crowded 
  with 
  

   minute 
  spherical 
  bacteria 
  in 
  active 
  movement. 
  The 
  contents 
  

   of 
  the 
  seminal 
  vesicles 
  of 
  some 
  of 
  those 
  individuals 
  (from 
  the 
  

   same 
  plot 
  of 
  ground) 
  which 
  possessed 
  a 
  clitellum 
  were 
  also 
  

   not 
  entirely 
  normal, 
  a 
  certain 
  proportion 
  of 
  the 
  sperm 
  mother- 
  

   cells 
  containing 
  the 
  bacteria. 
  

  

  The 
  greater 
  number 
  of 
  the 
  bacteria 
  are 
  spherical, 
  measuring 
  

   about 
  *0014 
  mm. 
  in 
  diameter 
  ; 
  others 
  are 
  elongated, 
  measuring 
  

   '007 
  by 
  '0014 
  mm. 
  Sometimes 
  distinctly 
  larger 
  individuals 
  

   occur, 
  measuring 
  *0035 
  by 
  *0043 
  mm. 
  

  

  In 
  all 
  the 
  infected 
  worms 
  the 
  seminal 
  vesicles 
  contained 
  

   unusually 
  large 
  numbers 
  of 
  Monocystis 
  — 
  spores, 
  cysts, 
  and 
  

   free 
  swimming 
  individuals, 
  but 
  not 
  the 
  attached 
  form. 
  

  

  In 
  all 
  cases 
  the 
  amoebocytes 
  were 
  conspicuous 
  in 
  the 
  

   seminal 
  vesicles, 
  and 
  were 
  crowded 
  with 
  ingested 
  and 
  now 
  

   motionless 
  individuals 
  of 
  the 
  bacterium 
  in 
  question. 
  In 
  this 
  

   connexion 
  Brasil's 
  remarks 
  are 
  interesting 
  (i) 
  : 
  — 
  " 
  La 
  

   presence 
  d'amibocytes 
  nombreux 
  dans 
  les 
  ve'sicules 
  seminales 
  

   des 
  Lumbricus 
  est 
  normale 
  et 
  connue. 
  Les 
  atnibocytes 
  

   seraient 
  attires 
  dans 
  ces 
  organes, 
  a-t-on 
  dit, 
  par 
  les 
  parasites 
  

   qui 
  y 
  abondent 
  presque 
  toujours 
  (Gregarines 
  du 
  genre 
  Mono- 
  

   cystis) 
  et 
  contribueraient 
  par 
  leurs 
  proprietes 
  phagocytaires 
  a 
  

   prewenir 
  un 
  encombrement 
  qui, 
  s'il 
  n'e*tait 
  entrave, 
  abouti- 
  

   rait 
  fatalement 
  a 
  la 
  castration 
  tout 
  au 
  moins 
  partielle 
  de 
  

   l'hote." 
  Brasil, 
  however, 
  thinks 
  lhat 
  the 
  amoebocytes 
  have 
  

   another 
  and 
  more 
  general 
  function 
  : 
  — 
  " 
  Le 
  rdle 
  principale 
  des 
  

   amibocytes 
  des 
  ve^icules 
  se"minales 
  consisterait 
  dans 
  le 
  nettoy- 
  

   age 
  complet 
  de 
  ces 
  organes 
  apies 
  les 
  Amissions 
  spermatiques. 
  

   . 
  . 
  . 
  L'action 
  sur 
  les 
  parasites 
  ne 
  serait 
  qu'un 
  episode 
  particu- 
  

   lier 
  de 
  cette 
  f'onction 
  plus 
  gene'rale." 
  

  

  I 
  have 
  never 
  observed 
  this 
  asserted 
  resorption 
  of 
  the 
  repro- 
  

   ductive 
  elements 
  by 
  the 
  phagocytes 
  : 
  in 
  those 
  instances 
  in 
  

   which 
  I 
  have 
  found 
  the 
  seminal 
  vesicles 
  of 
  the 
  earthworm 
  

   containing 
  only 
  amoebocytes 
  charged 
  witli 
  granules, 
  as 
  Brasil 
  

   describes, 
  the 
  condition 
  has 
  been 
  brought 
  about 
  by 
  the 
  

   bacterial 
  destruction 
  of 
  the 
  spermatic 
  elements. 
  

  

  This 
  bacterium 
  is 
  probably 
  as 
  constant 
  an 
  occupant 
  of 
  the 
  

   seminal 
  vesicles 
  of 
  the 
  earthworm 
  as 
  is 
  Monocystis. 
  I 
  have 
  

   found 
  it 
  in 
  small 
  numbers 
  in 
  healthy 
  worms 
  obtained 
  from 
  

   various 
  places. 
  In 
  a 
  healthy 
  worm, 
  however, 
  the 
  majority 
  

   of 
  the 
  bacteria 
  are 
  ingested 
  by 
  the 
  amoebocytes 
  and 
  are 
  

   consequently 
  motionless 
  ; 
  often 
  great 
  crowds 
  of 
  bacteria 
  are 
  

   seen 
  in 
  the 
  amcebccytes, 
  while 
  living 
  individuals 
  are 
  only 
  

   found 
  by 
  searching. 
  Their 
  inconspicuousness 
  when 
  motion- 
  

  

  