﻿26 
  CONTAGIOUS 
  DISEASES 
  OF 
  THE 
  CHINCH-BUG. 
  

  

  trichum. 
  On 
  June 
  28 
  Empusa 
  ap 
  hid 
  is 
  was 
  first 
  noticed 
  in 
  the 
  infecting 
  case. 
  

   Up 
  to 
  this 
  date 
  it 
  had 
  not 
  made 
  its 
  appearance 
  in 
  our 
  laboratory. 
  From 
  this 
  

   time 
  till 
  the 
  middle 
  of 
  August 
  it 
  multiplied 
  its 
  victims 
  in 
  the 
  infecting 
  cases. 
  

   For 
  a 
  short 
  time 
  it 
  became 
  more 
  conspicuous 
  than 
  Sporotrichum, 
  and 
  then 
  

   subsided. 
  

  

  On 
  July 
  4 
  we 
  began 
  experimenting 
  with 
  common, 
  shallow 
  dry-goods 
  

   boxes 
  for 
  infecting 
  cases. 
  The 
  inside 
  of 
  the 
  boxes 
  was 
  sprinkled, 
  and 
  the 
  

   bottoms 
  thickly 
  covered 
  with 
  green 
  wheat. 
  A 
  few 
  fungus-covered 
  bugs 
  were 
  

   sprinkled 
  over 
  the 
  wheat, 
  and 
  new 
  bugs 
  from 
  the 
  field 
  were 
  put 
  in 
  in 
  large 
  

   numbers. 
  Within 
  a 
  week 
  the 
  white-fungus-covered 
  bugs 
  were 
  thickly 
  spread 
  

   over 
  the 
  bottoms, 
  and 
  in 
  places 
  the 
  white 
  bugs 
  were 
  literally 
  in 
  heaps. 
  Con- 
  

   tinued 
  experiments 
  showed 
  that 
  damp 
  wooden 
  boxes 
  offered 
  the 
  best 
  condi- 
  

   tions 
  for 
  the 
  development 
  of 
  the 
  fungus, 
  and 
  the 
  glass 
  cases 
  were 
  no 
  longer 
  

   used. 
  Sporotrichum, 
  like 
  most 
  fungi, 
  thrives 
  best 
  in 
  a 
  moist 
  atmosphere, 
  but 
  

   an 
  excess 
  of 
  water, 
  such 
  as 
  occurs 
  in 
  a 
  wet 
  soil, 
  or 
  along 
  the 
  sides 
  of 
  a 
  glass 
  

   case 
  where 
  the 
  vapor 
  often 
  becomes 
  condensed, 
  is 
  detrimental 
  to 
  its 
  develop- 
  

   ment. 
  In 
  the 
  wooden 
  boxes 
  the 
  atmosphere 
  was 
  abundantly 
  humid; 
  but 
  

   water 
  that 
  was 
  sprinkled 
  in 
  from 
  time 
  to 
  time, 
  or 
  that 
  became 
  condensed 
  on 
  

   the 
  sides 
  of 
  the 
  boxes, 
  was 
  at 
  once 
  absorbed 
  by 
  the 
  wood. 
  

  

  During 
  July 
  and 
  August 
  Sporotrichum 
  continued 
  to 
  spread 
  through 
  sue. 
  

   cessive 
  lots 
  of 
  fresh 
  bugs 
  from 
  the 
  fields. 
  Empusa 
  was 
  always 
  present, 
  but 
  

   was 
  not 
  so 
  conspicuous 
  in 
  its 
  ravages 
  as 
  Sporotrichum. 
  In 
  the 
  first 
  weeks 
  of 
  

   September 
  the 
  diseases 
  began 
  to 
  subside, 
  and 
  by 
  the 
  middle 
  of 
  October 
  

   neither 
  Sporotrichum 
  nor 
  Empusa 
  appeared 
  to 
  be 
  spreading 
  further. 
  

  

  SPOROTRICHUM 
  GLOBULIFERUM. 
  

  

  June 
  28th, 
  the"spores 
  of 
  Sporotrichum 
  were 
  transferred 
  by 
  means 
  of 
  a 
  steril- 
  

   ized 
  needle 
  from 
  the 
  dead 
  body 
  of 
  a 
  chinch 
  bug 
  to 
  15 
  culture 
  plates. 
  The 
  

   culture 
  medium 
  was 
  a 
  mixture 
  of 
  beef 
  broth 
  and 
  Irish 
  moss, 
  enough 
  of 
  the 
  

   mucilaginous 
  decoction 
  of 
  the 
  moss 
  being 
  added 
  to 
  the 
  beef 
  broth 
  to 
  give 
  a 
  

   solid 
  medium 
  at 
  80 
  F. 
  Within 
  48 
  hours 
  the 
  spores 
  had 
  germinated, 
  and 
  

   branching 
  mycelia 
  could 
  be 
  seen 
  spreading 
  through 
  the 
  medium. 
  Within 
  

   three 
  days 
  spores 
  were 
  produced 
  in 
  abundance, 
  but 
  only 
  one 
  spot 
  on 
  one 
  of 
  

   the 
  15 
  plates 
  was 
  found 
  to 
  be 
  a 
  pure 
  culture, 
  Aspergillus 
  mucor 
  and 
  bacteria 
  

   being 
  mixed 
  with 
  all 
  the 
  other 
  growths 
  of 
  Sporotrichum. 
  From 
  the 
  one 
  pure 
  

   spot 
  spores 
  were 
  transferred 
  to 
  three 
  new 
  plates, 
  and 
  the 
  resulting 
  growths 
  

   were 
  all 
  pure. 
  

  

  The 
  germinating 
  spore 
  puts 
  forth 
  a 
  mycelium 
  which 
  branches 
  as 
  it 
  grows 
  

   ( 
  Plate 
  II, 
  fig. 
  8). 
  At 
  intervals 
  mycelial 
  branches 
  shoot 
  upwards 
  and 
  grow 
  

   over 
  the 
  surface 
  of 
  the 
  culture 
  medium, 
  producing 
  a 
  delicate 
  network 
  by 
  

   frequent 
  anastomoses, 
  bearing 
  dense 
  clusters 
  of 
  conidia 
  at 
  short 
  intervals 
  

   (Plate 
  II, 
  fig. 
  9). 
  A 
  portion 
  of 
  a 
  spore-bearing 
  mycelium 
  is 
  shown 
  more 
  

   highly 
  magnified 
  in 
  Plate 
  II, 
  fig. 
  10. 
  It 
  will 
  be 
  seen 
  that 
  the 
  conidia 
  are 
  

   either 
  borne 
  few 
  in 
  a 
  cluster 
  at 
  the 
  apex 
  of 
  a 
  simple 
  conidiophore, 
  or 
  the 
  

   conidiophore 
  becomes 
  branched, 
  with 
  the 
  conidia 
  apparently 
  sessile 
  at 
  or 
  near 
  

   the 
  apex 
  of 
  the 
  branches, 
  or 
  the 
  conidia 
  are 
  sessile 
  along 
  a 
  somewhat 
  zigzag 
  

  

  