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  CONTAGIOUS 
  DISEASES 
  OF 
  THE 
  CHINCH-BUG. 
  

  

  ferred 
  from 
  the 
  vast 
  abundance 
  of 
  this 
  species 
  on 
  chinch-bugs 
  in 
  the 
  field 
  very 
  

   recently 
  dead, 
  where 
  they 
  were 
  perishing 
  rapidly 
  and 
  in 
  enormous 
  numbers, 
  the 
  

   suddenness 
  with 
  which 
  it 
  bursts 
  out 
  of 
  the 
  body 
  after 
  death 
  in 
  the 
  form 
  of 
  a 
  spore- 
  

   bearing 
  growth, 
  (scarcely 
  to 
  be 
  accounted 
  for 
  except 
  on 
  the 
  supposition 
  that 
  it 
  had 
  

   infested 
  the 
  body 
  of 
  the 
  insect 
  while 
  the 
  latter 
  was 
  still 
  alive,) 
  and 
  the 
  absence 
  in 
  

   these 
  cases 
  of 
  any 
  other 
  apparent 
  cause 
  of 
  death. 
  Strong 
  corroboration 
  is 
  afforded 
  

   by 
  the 
  fact 
  that 
  this 
  fungus 
  has 
  been 
  found 
  an 
  open-air 
  parasite 
  upon 
  a 
  variety 
  of 
  

   other 
  insect 
  species, 
  and 
  that 
  it 
  has 
  been 
  lately 
  conveyed 
  to 
  a 
  great 
  variety 
  of 
  per- 
  

   fectly 
  healthy 
  insects 
  by 
  exposure, 
  both 
  to 
  chinch-bugs 
  and 
  to 
  other 
  insect 
  species 
  

   on 
  which 
  it 
  had 
  matured 
  its 
  spores, 
  and 
  by 
  treatment 
  with 
  this 
  fungus 
  obtained 
  in 
  

   quantity 
  by 
  artificial 
  cultivation. 
  

  

  Professor 
  Forbes 
  then 
  proceeds, 
  in 
  his 
  " 
  Notes," 
  to 
  give 
  in 
  detail 
  an 
  account 
  

   of 
  his 
  culture 
  experiments 
  with 
  the 
  Micrococcus 
  and 
  Sporotrichum. 
  The 
  first 
  

   attempts 
  at 
  the 
  artificial 
  culture 
  of 
  the 
  Micrococcus 
  in 
  his 
  laboratory 
  were 
  

   made 
  by 
  an 
  assistant, 
  September 
  1-3, 
  1886. 
  The 
  bugs 
  used 
  were 
  apparently 
  

   free 
  from 
  the 
  bacterial 
  disease, 
  so 
  that 
  no 
  cultures 
  were 
  obtained. 
  The 
  next 
  

   attempt 
  was 
  on 
  September 
  25, 
  1888, 
  "with 
  a 
  tube 
  of 
  solid 
  gelatine 
  infected 
  

   from 
  the 
  fluids 
  of 
  a 
  young 
  chinch-bug 
  in 
  the 
  third 
  stage 
  of 
  its 
  growth." 
  

  

  He 
  says 
  further: 
  

  

  . 
  . 
  . 
  This 
  insect 
  was 
  taken 
  from 
  a 
  corn 
  field 
  at 
  Odin, 
  111., 
  where 
  chinch-bugs 
  

   were 
  noticeably 
  very 
  much 
  less 
  numerous 
  than 
  they 
  had 
  been 
  observed 
  to 
  be 
  

   some 
  weeks 
  before, 
  and 
  where, 
  also, 
  adults 
  were 
  present 
  in 
  noticeably 
  small 
  propor- 
  

   tion. 
  The 
  fluids 
  were 
  swarming 
  with 
  the 
  usual 
  Micrococci. 
  . 
  . 
  . 
  On 
  the 
  29th 
  of 
  

   September 
  a 
  profuse 
  growth 
  had 
  made 
  its 
  appearance 
  in 
  this 
  tube, 
  the 
  gelatine 
  be- 
  

   ing 
  considerably 
  liquefied 
  and 
  the 
  liquid 
  portion 
  slightly 
  milky, 
  but 
  the 
  bacterial 
  

   growth 
  having 
  mostly 
  settled 
  in 
  an 
  irregular, 
  flocculent 
  mass. 
  A 
  slide 
  made 
  at 
  this 
  

   time 
  shows 
  an 
  apparently 
  pure 
  culture 
  of 
  the 
  original 
  Micrococcus 
  insectorum, 
  so 
  far 
  

   as 
  may 
  be 
  determined 
  by 
  critical 
  microscopical 
  examination. 
  It 
  is 
  quite 
  certain, 
  

   however, 
  that 
  the 
  growth 
  was 
  mixed, 
  and 
  the 
  liquefaction 
  of 
  the 
  gelatine 
  was 
  prob- 
  

   ably 
  due 
  to 
  another 
  form 
  than 
  the 
  chinch-bug 
  microbe, 
  especially 
  as 
  examinations 
  

   of 
  the 
  bacteria 
  when 
  fresh 
  showed 
  some 
  flagellate 
  movements 
  — 
  a 
  feature 
  never 
  seen 
  

   in 
  those 
  directly 
  from 
  the 
  insect. 
  

  

  A 
  fairly 
  satisfactory 
  attempt 
  at 
  the 
  culture 
  of 
  the 
  chinch-bug 
  Micrococcus 
  was 
  

   made 
  by 
  Professor 
  Burrill 
  in 
  the 
  bacterial 
  laboratory 
  of 
  the 
  university 
  in 
  October, 
  

   1888, 
  from 
  a 
  still 
  living 
  specimen 
  obtained 
  at 
  Mt. 
  Carmel, 
  111., 
  September 
  30. 
  The 
  

   chinch-bug 
  was 
  thoroughly 
  washed 
  before 
  crushing 
  in 
  corrosive 
  sublimate 
  solution 
  

   to 
  disinfect 
  the 
  surface, 
  and 
  was 
  then 
  crushed 
  in 
  freshly 
  distilled 
  water. 
  From 
  the 
  

   fluids 
  thus 
  obtained 
  a 
  solid 
  culture 
  was 
  begun 
  in 
  an 
  agar 
  tube 
  and 
  placed 
  in 
  the 
  in- 
  

   cubator. 
  October 
  3, 
  this 
  had 
  formed 
  two 
  very 
  small 
  colonies 
  of 
  rather 
  poor 
  and 
  

   irregular 
  growth, 
  but 
  seemingly 
  pure 
  Micrococcus 
  insectorum. 
  The 
  bacteria 
  were 
  

   usually 
  in 
  couples, 
  but 
  occasional 
  examples 
  were 
  of 
  irregular 
  form, 
  swollen 
  at 
  one 
  

   end 
  or 
  abnormally 
  slender, 
  peculiarities 
  traceable 
  perhaps 
  to 
  the 
  effect 
  of 
  the 
  cor- 
  

   rosive 
  sublimate. 
  

  

  Several 
  other 
  attempts 
  with 
  agar 
  and 
  gelatine 
  and 
  with 
  fluid 
  media 
  were 
  neither 
  

   more 
  or 
  less 
  successful 
  than 
  the 
  foregoing, 
  all 
  leaving 
  a 
  margin 
  of 
  doubt 
  whether 
  

   the 
  original 
  form 
  reappeared 
  in 
  the 
  culture, 
  a 
  doubt 
  which 
  could 
  only 
  be 
  removed 
  

   by 
  infection 
  of 
  healthy 
  insects 
  from 
  these 
  cultures 
  and 
  the 
  reappearance 
  under 
  such 
  

   circumstances, 
  in 
  the 
  alimentary 
  canal, 
  of 
  the 
  form 
  originally 
  occurring 
  there. 
  Un- 
  

   fortunately 
  for 
  the 
  conclusiveness 
  of 
  this 
  work, 
  it 
  was 
  impossible 
  to 
  find 
  at 
  any 
  

   time 
  when 
  these 
  cultures 
  were 
  in 
  progress 
  any 
  lot 
  of 
  chinch-bugs 
  which 
  would 
  not 
  

  

  