﻿107 
  

  

  so 
  rapidly 
  under 
  the 
  intiuence 
  of 
  this 
  disease 
  as 
  in 
  mere 
  decay, 
  their 
  

   firmness 
  being 
  rather 
  between 
  that 
  of 
  the 
  cabbage 
  worm 
  when 
  dead 
  

   with 
  its 
  characteristic 
  disease 
  — 
  the 
  so-called 
  white 
  plague 
  — 
  and 
  that 
  

   of 
  caterpillars 
  infested 
  by 
  fungus 
  parasites 
  which 
  give 
  origin 
  to 
  the 
  

   diseases 
  known 
  as 
  niuscardines. 
  

  

  Microscopic 
  examination 
  of 
  recently 
  dead 
  or 
  dying 
  caterpillars 
  

   showed 
  that 
  these 
  were 
  little 
  more 
  than 
  a 
  mere 
  gruel 
  of 
  minute, 
  

   slightly 
  angular, 
  highly 
  refracting 
  particles, 
  varying 
  in 
  size, 
  but 
  with 
  

   an 
  average 
  diameter 
  of 
  2.7 
  microns. 
  In 
  less 
  degenerate 
  parts 
  of 
  the 
  

   bodj- 
  these 
  particles 
  were 
  massed 
  in 
  more 
  or 
  less 
  spherical 
  bodies, 
  

   cell-like 
  in 
  form, 
  and 
  either 
  floating 
  free 
  in 
  the 
  fluids 
  or 
  collected 
  in 
  

   large 
  clusters 
  of 
  such 
  cells. 
  Comparison 
  with 
  the 
  fatty 
  bodies 
  of 
  the 
  

   insect 
  showed 
  that 
  the 
  spherical 
  bodies 
  were 
  detached 
  cells 
  of 
  that 
  

   tissue, 
  and 
  that 
  nearly 
  the 
  whole 
  substance 
  of 
  this 
  organ 
  was 
  practi- 
  

   cally 
  converted 
  into 
  these 
  minute 
  peculiar 
  granules. 
  Each 
  cell 
  in 
  

   such 
  a 
  diseased 
  tissue 
  was 
  an 
  opaque 
  collection 
  of 
  the 
  dark 
  spherical 
  

   granules, 
  sometimes 
  surrounded 
  by 
  a 
  more 
  or 
  less 
  continuous 
  layer 
  

   of 
  ordinary 
  oil 
  globules. 
  This 
  degeneration 
  of 
  the 
  fatty 
  bodies 
  was 
  

   in 
  fact 
  the 
  most 
  marked 
  peculiarity 
  of 
  the 
  disease, 
  a 
  point 
  in 
  which 
  

   it 
  agrees 
  with 
  the 
  so-called 
  "yellows" 
  or 
  jaundice 
  of 
  the 
  silkworm 
  as 
  

   described 
  by 
  me 
  in 
  1886.* 
  The 
  cells 
  of 
  the 
  Malpighian 
  tubules 
  were 
  

   similarly 
  degenerated. 
  

  

  Besides 
  these 
  various 
  products 
  of 
  degeneration 
  derived 
  from 
  the 
  

   fatty 
  bodies, 
  the 
  fluids 
  of 
  the 
  diseased 
  caterpillars 
  contained 
  three 
  

   other 
  classes 
  of 
  cellular 
  elements 
  in 
  sufficient 
  abundance 
  to 
  make 
  

   them 
  worthy 
  of 
  notice. 
  Normal 
  blood 
  corpuscles 
  Avere 
  still 
  recog- 
  

   nizable 
  in 
  caterpillars 
  not 
  too 
  far 
  gone 
  with 
  disease. 
  They 
  were 
  com- 
  

   monly 
  rather 
  few 
  in 
  number 
  and 
  spherical 
  in 
  form, 
  with 
  a 
  great 
  num- 
  

   ber 
  of 
  minute 
  hair-like 
  pseudopods. 
  

  

  Mingled 
  with 
  these, 
  and 
  in 
  badly 
  diseased 
  specimens 
  much 
  more 
  

   abundant, 
  was 
  a 
  class 
  of 
  amceboid 
  cells 
  distinguishable 
  at 
  a 
  glance 
  

   from 
  normal 
  blood 
  corpuscles, 
  but, 
  nevertheless, 
  possibly 
  derived 
  from 
  

   them, 
  their 
  peculiar 
  condition 
  being 
  perhaps 
  the 
  result 
  of 
  changes 
  

   induced 
  by 
  disease. 
  These 
  were 
  pale 
  protoplasmic 
  cells 
  without 
  dis- 
  

   tinguishable 
  wall, 
  with 
  very 
  little 
  distinction 
  of 
  ectoplasm 
  and 
  en- 
  

   doplasm, 
  and 
  commonly 
  with 
  two 
  or 
  three 
  pseudopods, 
  or 
  very 
  rarely 
  

   with 
  more, 
  usually 
  thick 
  at 
  their 
  origin 
  and 
  tapering 
  to 
  an 
  acute 
  

   point. 
  Sometimes 
  as 
  many 
  as 
  twenty 
  of 
  these 
  bodies 
  were 
  seen 
  in 
  a 
  

   single 
  field 
  of 
  the 
  microscope, 
  with 
  a 
  power 
  of 
  five 
  hundred 
  diame- 
  

   ters, 
  in 
  a 
  slide 
  made 
  from 
  the 
  blood. 
  Occasionally 
  one 
  was 
  seen 
  with 
  

   a 
  distinct 
  nucleus, 
  but 
  rarely 
  so 
  without 
  special 
  preparation. 
  The 
  

   protoplasm 
  was 
  homogeneous 
  though 
  very 
  finely 
  granular, 
  even 
  the 
  

   finest 
  pseudopods 
  being 
  commonly 
  granular 
  as 
  far 
  as 
  they 
  could 
  be 
  

   distinctly 
  traced. 
  Vacuoles 
  of 
  any 
  sort 
  were 
  rarely 
  seen, 
  althougli 
  

   occasionally 
  one 
  or 
  two 
  small 
  pale 
  circular 
  areas 
  were 
  discoverable 
  

   within 
  the 
  cytoplasm. 
  The 
  cell 
  was 
  commonly 
  more 
  or 
  less 
  definitely 
  

   spindle-shaped, 
  with 
  a 
  thick 
  median 
  portion, 
  and 
  the 
  spindle 
  was 
  

   often 
  bent 
  to 
  one 
  side, 
  sometimes 
  so 
  much 
  as 
  to 
  give 
  the 
  cell 
  a 
  semi- 
  

   circular 
  form, 
  the 
  pseudopods 
  starting 
  from 
  the 
  angles 
  of 
  the 
  semi- 
  

  

  * 
  Bull. 
  111. 
  State 
  Lab. 
  Nat. 
  Hist, 
  Vol. 
  II.. 
  Art. 
  IV.. 
  p. 
  280. 
  

  

  