﻿HISTORY 
  OF 
  THE 
  DISEASES 
  IN 
  THE 
  UNITED 
  STATES. 
  215 
  

  

  Concerning 
  the 
  utilization 
  of 
  artificial 
  cultures 
  of 
  Micrococcus 
  for 
  a 
  propagation 
  

   of 
  this 
  disease 
  among 
  insects 
  not 
  affected, 
  I 
  am 
  at 
  present 
  able 
  to 
  say 
  but 
  little, 
  as 
  

   I 
  have 
  not 
  yet 
  succeeded, 
  in 
  either 
  season 
  when 
  it 
  was 
  common, 
  in 
  finding 
  lots 
  of 
  

   chinch-bugs 
  sufficiently 
  free 
  from 
  it 
  to 
  make 
  them 
  suitable 
  subjects 
  for 
  experimen- 
  

   tal 
  attempts 
  at 
  its 
  transfer. 
  It 
  will 
  be 
  readily 
  understood 
  by 
  anyone 
  that 
  it 
  is 
  use- 
  

   less 
  to 
  test 
  the 
  utility 
  of 
  artificial 
  cultures 
  of 
  the 
  disease 
  germs 
  by 
  applying 
  them 
  to 
  

   insects 
  which 
  are 
  already 
  affected 
  by 
  the 
  disease 
  in 
  question. 
  The 
  first 
  step 
  of 
  any 
  

   really 
  scientific 
  investigation 
  of 
  the 
  economics 
  of 
  this 
  matter 
  is, 
  to 
  determine 
  posi- 
  

   tively 
  the 
  absence 
  of 
  the 
  disease 
  in 
  the 
  lots 
  of 
  insects 
  to 
  be 
  used 
  in 
  the 
  experiments. 
  

   Every 
  lot 
  of 
  chinch-bugs 
  thus 
  far 
  obtained 
  by 
  me 
  from 
  central, 
  south 
  central 
  and 
  

   northern 
  Illinois 
  during 
  the 
  months 
  of 
  July 
  and 
  August 
  of 
  this 
  year 
  gave 
  evidence, 
  

   under 
  critical 
  study, 
  of 
  the 
  presence 
  of 
  this 
  microbe 
  in 
  the 
  coeca 
  of 
  a 
  larger 
  or 
  

   smaller 
  percentage 
  of 
  pupre 
  and 
  imagos. 
  My 
  previous 
  observations 
  — 
  less 
  carefully 
  

   made, 
  however, 
  than 
  my 
  recent 
  ones 
  —have 
  been 
  to 
  the 
  general 
  effect 
  that 
  hibernat- 
  

   ing 
  chinch-bugs 
  and 
  young, 
  preceding 
  the 
  so-called 
  pupa 
  state, 
  are 
  little 
  liable 
  to 
  

   the 
  spontaneous 
  occurrence 
  of 
  the 
  intestinal 
  trouble, 
  and 
  I 
  consequently 
  do 
  not 
  de- 
  

   spair 
  of 
  finding, 
  before 
  the 
  present 
  season 
  is 
  over, 
  opportunity 
  for 
  experiments 
  

   which 
  will 
  determine 
  beyond 
  question 
  the 
  economic 
  value 
  of 
  this 
  chinch-bug 
  

   "cholera." 
  

  

  In 
  a 
  yet 
  later 
  paper, 
  entitled 
  " 
  Bacteria 
  Normal 
  to 
  Digestive 
  Organs 
  of 
  

   Hemiptera," 
  published 
  as 
  article 
  1, 
  Vol. 
  IV, 
  1892, 
  Bulletin 
  of 
  the 
  Illinois 
  

   State 
  Laboratory 
  of 
  Natural 
  History, 
  Professor 
  Forbes 
  records 
  the 
  finding 
  of 
  

   bacteria 
  in 
  organs 
  homologous 
  with 
  the 
  chinch-bug 
  coeca 
  in 
  many 
  of 
  the 
  

   higher 
  hemiptera. 
  There 
  appear 
  to 
  be 
  distinct 
  bacterial 
  forms 
  differing 
  

   in 
  the 
  various 
  hemipteral 
  species 
  examined. 
  These 
  bacteria 
  are 
  found 
  only 
  

   in 
  the 
  coeca. 
  Professsor 
  Forbes 
  says 
  : 
  " 
  In 
  every 
  case 
  where 
  they 
  have 
  oc- 
  

   curred 
  in 
  our 
  dissections, 
  we 
  have 
  made 
  exhaustive 
  search 
  for 
  bacteria 
  in 
  

   other 
  parts 
  of 
  the 
  alimentary 
  canal 
  also, 
  and 
  in 
  the 
  salivary 
  glands, 
  the 
  fatty 
  

   bodies, 
  etc., 
  and 
  in 
  all 
  these 
  hemiptera 
  with 
  only 
  negative 
  results." 
  In 
  con- 
  

   cluding 
  the 
  paper, 
  Professor 
  Forbes 
  says 
  : 
  

  

  I 
  have 
  no 
  present 
  desire 
  to 
  speculate 
  concerning 
  the 
  meaning 
  of 
  the 
  bacterial 
  

   contents 
  of 
  these 
  glands, 
  but 
  limit 
  myself 
  to 
  this 
  preliminary 
  account, 
  and 
  await 
  

   the 
  completion 
  of 
  the 
  several 
  investigations 
  in 
  which 
  we 
  are 
  now 
  engaged, 
  upon 
  

   the 
  distribution 
  of 
  the 
  coeca, 
  their 
  variations, 
  and 
  their 
  relations 
  to 
  the 
  habits 
  of 
  

   the.species 
  possessing 
  them, 
  and 
  upon 
  the 
  kinds 
  and 
  nature 
  of 
  the 
  bacteria 
  con- 
  

   stantly 
  harbored 
  by 
  these 
  interesting 
  appendages 
  of 
  the 
  alimentary 
  canal. 
  

  

  Concerning 
  their 
  relations 
  to 
  insect 
  disease, 
  I 
  will 
  only 
  add 
  that, 
  in 
  chinch-bugs 
  

   perishing 
  gradually 
  but 
  rapidly, 
  we 
  find 
  them 
  varying 
  considerably 
  in 
  number 
  in 
  the 
  

   coecal 
  appendages, 
  and 
  that 
  where 
  they 
  are 
  most 
  abundant 
  the 
  epithelium 
  of 
  these 
  

   structures 
  is 
  completely 
  disorganized, 
  only 
  the 
  basement 
  membrane 
  remaining 
  in 
  

   the 
  form 
  of 
  coecal 
  tubes 
  filled 
  with 
  a 
  pure 
  culture 
  of 
  Micrococcus 
  insectorum 
  and 
  a 
  

   little 
  granular 
  debris, 
  the 
  latter 
  apparently 
  the 
  product 
  of 
  the 
  decomposition 
  of 
  the 
  

   epithelium. 
  

  

  