﻿* 
  

  

  256 
  BOTANICAL 
  GAZETTE. 
  [October, 
  

  

  SO' 
  

  

  chambers 
  and 
  kept 
  there 
  for 
  a 
  week 
  ; 
  a 
  large 
  number 
  of 
  

   clusters 
  were 
  brought 
  into 
  the 
  laborator}-, 
  and, 
  after 
  being 
  in- 
  

   oculated, 
  were 
  placed 
  in 
  the 
  incubator, 
  where 
  a 
  constant 
  tem- 
  

   perature 
  of 
  32° 
  C. 
  prevailed. 
  At 
  the 
  expiration 
  of 
  four 
  days 
  

   the 
  berries 
  in 
  the 
  incubator 
  would 
  usually 
  turn 
  brown, 
  but 
  

   microscopic 
  examination 
  revealed 
  the 
  fact 
  that 
  this 
  was 
  due 
  

   to 
  the 
  attacks 
  of 
  moulds 
  and 
  bacteria. 
  

  

  In 
  the 
  majority 
  of 
  cases 
  the 
  inoculations 
  were 
  made 
  by 
  

   teasing 
  up 
  a 
  bit 
  of 
  the 
  affected 
  leaf 
  in 
  water, 
  and 
  after 
  mak- 
  

   ing 
  sure, 
  by 
  means 
  of 
  the 
  microscope, 
  that 
  this 
  water 
  con- 
  

   tained 
  spores, 
  it 
  was 
  allowed 
  to 
  stand 
  from 
  twenty-four 
  to 
  

   thirty-six 
  hours, 
  or 
  until 
  the 
  spores 
  had 
  germinated. 
  The 
  

   water 
  was 
  then 
  spread 
  on 
  the 
  berries 
  with 
  a 
  camels 
  hair 
  

   brush. 
  In 
  addition 
  to 
  this 
  method, 
  others, 
  such 
  as 
  using 
  

   spores 
  fresh 
  from 
  the 
  leaf, 
  and 
  spores 
  sown 
  in 
  3 
  per 
  cent, 
  

   hitions 
  of 
  grape 
  sugar, 
  were 
  tried. 
  Various 
  degrees 
  of 
  light 
  

   from 
  absolute 
  darkness 
  to 
  bright 
  sunshine 
  were 
  also 
  brought 
  

   into 
  play, 
  all 
  with 
  the 
  same 
  result. 
  To 
  test 
  the 
  matter 
  an- 
  

   other 
  way, 
  sowings 
  of 
  pycnidia-spores 
  from 
  the 
  berries 
  were 
  

   made 
  on 
  the 
  leaves, 
  the 
  result 
  being 
  purely 
  negative 
  in 
  every 
  

   case, 
  Pycnidia-spores 
  frorh 
  the 
  berries 
  were 
  also 
  sown 
  on 
  the 
  

   berries, 
  but 
  in 
  no 
  case 
  did 
  we 
  succeed 
  in 
  obtaining 
  any 
  defi- 
  

   nite 
  results 
  from 
  this 
  source. 
  

  

  The 
  foregoing 
  experiments 
  were 
  made 
  in 
  1889. 
  This 
  

   season 
  the 
  same 
  ground 
  was 
  gone 
  over 
  with 
  practically 
  the 
  

   same 
  results 
  as 
  those 
  already 
  noted. 
  In 
  addition, 
  however, 
  

   a 
  series 
  of 
  inoculations 
  were 
  made 
  with 
  the 
  ascospores 
  ot 
  

   the 
  Lastadia, 
  and, 
  as 
  these 
  yielded 
  more 
  definite 
  results, 
  we 
  

   shall 
  give 
  an 
  account 
  of 
  the 
  work 
  in 
  full. 
  , 
  , 
  

  

  In 
  tlie 
  fall 
  of 
  1889 
  a 
  large 
  quantity 
  of 
  berries 
  which 
  hao 
  

   succumbed 
  to 
  the 
  attacks 
  of 
  black-rot 
  a 
  few 
  months 
  before 
  

   were 
  collected 
  from 
  the 
  vines 
  growing 
  in 
  the 
  grounds 
  of 
  the 
  

   United 
  States 
  Department 
  of 
  Agriculture. 
  These 
  berries 
  

   were 
  placed 
  in 
  a 
  corner 
  of 
  my 
  garden 
  where 
  they 
  were 
  le 
  

   lully 
  exposed 
  to 
  the 
  weather 
  until 
  the 
  middle 
  of 
  May 
  o( 
  tf 
  

   year. 
  l<requent 
  microscopic 
  examinations 
  were 
  made 
  m 
  J 
  

   meantime 
  for 
  the 
  purpose 
  of 
  determining 
  the 
  date 
  of 
  th 
  

   hrst 
  appearance 
  of 
  mature 
  ascospores, 
  which, 
  we 
  may 
  as 
  w 
  

   add 
  here, 
  was 
  the 
  15th 
  of 
  February. 
  From 
  this 
  time 
  on 
  i^ 
  

   ascospores 
  w^ere 
  found 
  in 
  more 
  or 
  less 
  abundance, 
  the 
  ^f' 
  

  

  May 
  

  

  altogether 
  by 
  the 
  20th 
  of 
  Tune 
  I 
  

   spores 
  found 
  in 
  any 
  of 
  the 
  berries. 
  

  

  