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  REPOET 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  not 
  be 
  difficult 
  to 
  obtain 
  even 
  a 
  more 
  rapid 
  growth 
  in 
  the 
  most 
  

   favorable 
  localities. 
  

  

  Coviparatlve 
  growth 
  on 
  high 
  and 
  loio 
  heach. 
  — 
  Several 
  thousand 
  clams 
  

   were 
  planted 
  in 
  rows 
  extending 
  from 
  the 
  high-tide 
  mark 
  to 
  a 
  position 
  

   some 
  distance 
  below 
  ordinary 
  low 
  water, 
  in 
  order 
  to 
  determine, 
  if 
  

   possible, 
  the 
  relative 
  effects 
  of 
  long-continued 
  submergence 
  and 
  fre- 
  

   quent 
  exposure. 
  Unfortunately 
  the 
  attempt 
  failed, 
  because, 
  in 
  igno- 
  

   rance 
  of 
  the 
  number 
  which 
  a 
  given 
  area 
  would 
  support 
  on 
  these 
  

   beaches, 
  the 
  clams 
  were 
  placed 
  so 
  close 
  together 
  that 
  they 
  all 
  died. 
  

   That 
  fact 
  itself 
  is 
  one 
  of 
  the 
  most 
  important 
  demonstrated 
  by 
  these 
  

   experiments, 
  and 
  will 
  be 
  mentioned 
  later. 
  

  

  Among 
  the 
  IT 
  beds 
  at 
  the 
  head 
  of 
  the 
  harbor 
  were 
  several 
  which 
  

   were 
  exposed 
  only 
  at 
  full-moon 
  tide. 
  It 
  is 
  a 
  curious 
  fact, 
  for 
  which 
  

   there 
  is 
  no 
  apparent 
  explanation, 
  that 
  in 
  almost 
  all 
  of 
  these 
  the 
  greater 
  

   number 
  of 
  clams 
  died. 
  They 
  were 
  not 
  more 
  thickly 
  planted 
  than 
  on 
  

   higher 
  beds, 
  though 
  their 
  average 
  size 
  was 
  slightly 
  larger. 
  On 
  the 
  

   other 
  hand, 
  as 
  already 
  stated, 
  a 
  very 
  rapid 
  growth 
  was 
  obtained 
  in 
  

   another 
  locality 
  on 
  a 
  bed 
  placed 
  near 
  the 
  ordinary 
  low- 
  water 
  mark, 
  

   the 
  lower 
  part 
  of 
  it 
  usual!}' 
  being 
  submerged. 
  

  

  Death 
  from 
  overcroiDdhig 
  . 
  — 
  This 
  may 
  be 
  due, 
  as 
  in 
  the 
  case 
  of 
  the 
  

   small 
  clams, 
  to 
  two 
  things 
  — 
  the 
  lack 
  of 
  sufficient 
  food 
  and 
  the 
  con- 
  

   tamination 
  of 
  the 
  water 
  by 
  the 
  decaying 
  bodies 
  of 
  dead 
  clams. 
  Vvlien 
  

   a 
  clam 
  dies 
  others 
  near 
  it 
  seem 
  to 
  be 
  affected. 
  When 
  several 
  die 
  the 
  

   infection 
  seems 
  to 
  spread 
  rapidly, 
  so 
  that 
  the 
  death 
  of 
  a 
  few 
  may 
  lead 
  

   to 
  the 
  sudden 
  destruction 
  of 
  man}' 
  or 
  all 
  in 
  the 
  vicinity. 
  To 
  illustrate 
  

   this, 
  two 
  beds 
  were 
  planted 
  thickly 
  (9 
  to 
  a 
  square 
  foot) 
  with 
  clams 
  \% 
  

   inches 
  long. 
  Among 
  these 
  were 
  a 
  few 
  individuals 
  which 
  were 
  nearly 
  

   dead 
  from 
  exposure. 
  Their 
  bodies 
  probably 
  quickly 
  disintegrated. 
  

   The 
  majority 
  in 
  each 
  bed 
  were 
  apparently 
  in 
  the 
  best 
  condition. 
  

  

  One 
  of 
  these 
  beds 
  was 
  in 
  comparatively 
  quiet 
  water; 
  the 
  otherwhere 
  

   currents 
  were 
  constantly 
  running 
  back 
  and 
  forth 
  over 
  it. 
  A 
  year 
  after 
  

   planting, 
  the 
  first 
  bed 
  contained 
  no 
  living 
  clams. 
  The 
  shells 
  of 
  the 
  dead 
  

   were 
  easily 
  found, 
  though 
  in 
  some 
  cases 
  nearly 
  disintegrated. 
  When 
  

   measured 
  the}' 
  were 
  found 
  to 
  be, 
  without 
  exception, 
  the 
  size 
  of 
  those 
  

   planted. 
  This 
  indicates 
  that 
  the 
  few 
  injured 
  clams 
  died 
  at 
  once 
  after 
  

   planting 
  and 
  that 
  the 
  contamination 
  spread 
  rapidly, 
  all 
  being 
  destroyed 
  

   before 
  any 
  had 
  grown. 
  

  

  The 
  other 
  bed, 
  in 
  the 
  more 
  rapid 
  current, 
  contained 
  a 
  few 
  living 
  

   clams. 
  A 
  great 
  number 
  of 
  empty 
  shells 
  was 
  found, 
  but 
  these 
  were 
  

   not 
  all 
  of 
  one 
  size, 
  as 
  in 
  the 
  first 
  case. 
  They 
  exhibited 
  a 
  gradation 
  

   from 
  the 
  size 
  of 
  the 
  living 
  forms, 
  which 
  were 
  the 
  largest, 
  to 
  shells 
  of 
  

   the 
  planted 
  clams. 
  The 
  condition 
  of 
  this 
  bed 
  probably 
  is 
  to 
  be 
  

   explained 
  by 
  the 
  supposition 
  that 
  the 
  early 
  death 
  of 
  a 
  few 
  injured 
  

   forms 
  did 
  not 
  immediately 
  affect 
  all 
  the 
  others, 
  this 
  being 
  prevented 
  

  

  