﻿OYSTER 
  INDU8TKY 
  OF 
  NORTH 
  CAROLINA. 
  253 
  

  

  the 
  food 
  of 
  Chesapeake 
  oysters, 
  but 
  they 
  do 
  not 
  show 
  the 
  food 
  vahie 
  of 
  

   the 
  water. 
  In 
  his 
  report 
  on 
  the 
  oyster 
  beds 
  of 
  Louisiana, 
  Moore 
  « 
  

   gives 
  the 
  actual 
  amount 
  of 
  food 
  found 
  in 
  a 
  given 
  quantity 
  of 
  the 
  water 
  

   taken 
  over 
  the 
  best 
  oyster 
  beds, 
  the 
  calculations 
  based 
  on 
  examina- 
  

   tions 
  with 
  the 
  microscope 
  and 
  the 
  Rafter 
  cell. 
  A 
  vevy 
  similar 
  method 
  

   was 
  employed 
  in 
  my 
  work, 
  but 
  before 
  describing 
  it 
  the 
  method 
  used 
  

   by 
  Bashford 
  Dean 
  ^ 
  in 
  dealing 
  with 
  the 
  same 
  problem 
  in 
  the 
  oyster 
  

   survey 
  of 
  South 
  Cai'olina 
  waters 
  may 
  appropriately 
  be 
  discussed. 
  

   Dean 
  used 
  a 
  chemical 
  test 
  in 
  determining 
  the 
  food 
  value 
  of 
  the 
  water, 
  

   the 
  amount 
  of 
  albuminoid 
  ammonia 
  being 
  taken 
  as 
  representing 
  the 
  

   amount 
  of 
  available 
  oyster 
  food, 
  or 
  at 
  least 
  supplying 
  data 
  from 
  which 
  

   the 
  relative 
  value 
  of 
  different 
  localities 
  for 
  oyster 
  culture 
  might 
  be 
  

   compared. 
  In 
  obtaining 
  a 
  specimen 
  of 
  water 
  for 
  anal^^sis 
  he 
  pro- 
  

   ceeded 
  as 
  follows: 
  Two 
  liters 
  of 
  water 
  was 
  collected 
  1 
  foot 
  from 
  the 
  

   bottom 
  over 
  the 
  oyster 
  grounds, 
  brought 
  to 
  the 
  laborator}-, 
  and 
  after 
  

   being 
  vigorously 
  agitated 
  was 
  allowed 
  to 
  stand 
  for 
  a 
  few 
  minutes 
  so 
  

   that 
  the 
  sediment 
  might 
  settle. 
  A 
  sufficient 
  quantity 
  of 
  water 
  for 
  

   analysis 
  was 
  then 
  taken 
  from 
  the 
  middle 
  of 
  the 
  jar. 
  It 
  is 
  here 
  sup- 
  

   posed, 
  as 
  is 
  shown 
  by 
  the 
  following 
  quotation, 
  that 
  the 
  organisms 
  

   which 
  constitute 
  the 
  food 
  of 
  the 
  oysters 
  will 
  remain 
  suspended, 
  while 
  

   the 
  organic 
  impurities 
  will 
  have 
  settled: 
  "The 
  specimen 
  represents 
  

   the 
  average 
  prevalence 
  of 
  oyster 
  food 
  in 
  the 
  given 
  locality, 
  and, 
  if 
  

   properly 
  collected, 
  it 
  may 
  be 
  proven 
  by 
  the 
  microscope 
  to 
  be 
  practi- 
  

   cally 
  free 
  from 
  the 
  organic 
  matters 
  which 
  should 
  not 
  be 
  included 
  in 
  the 
  

   food 
  of 
  the 
  oyster." 
  

  

  After 
  my 
  study 
  of 
  the 
  North 
  Carolina 
  oyster, 
  I 
  can 
  hardly 
  agree 
  

   that 
  the 
  above 
  method 
  is 
  in 
  any 
  way 
  reliable 
  in 
  the 
  data 
  it 
  sup- 
  

   plies, 
  and, 
  since 
  it 
  may 
  prove 
  to 
  be 
  of 
  economic 
  importance 
  to 
  be 
  able 
  

   to 
  determine, 
  previous 
  to 
  an 
  expensive 
  oyster-planting 
  operation, 
  the 
  

   food 
  resources 
  of 
  a 
  locality, 
  I 
  have 
  endeavored 
  to 
  perfect 
  a 
  method 
  

   which 
  will 
  be 
  fairly 
  accurate 
  in 
  its 
  results. 
  My 
  reasons 
  for 
  discard- 
  

   ing 
  Dean's 
  chemical 
  test 
  for 
  a 
  microscopical 
  examination 
  of 
  the 
  water 
  

   are: 
  (1) 
  No 
  matter 
  how 
  carefull}'^ 
  the 
  specimen 
  of 
  water 
  has 
  been 
  col- 
  

   lected 
  it 
  is 
  sure 
  to 
  contain 
  an 
  abundance 
  of 
  organic 
  impurities, 
  which 
  

   do 
  not 
  quickly 
  settle 
  but 
  remain 
  in 
  suspension 
  for 
  a 
  considerable 
  

   time 
  — 
  several 
  hours. 
  {'■2) 
  Among 
  the 
  first 
  things 
  to 
  settle 
  to 
  the 
  bot- 
  

   tom, 
  when 
  the 
  water 
  is 
  freed 
  from 
  currents, 
  are 
  some 
  of 
  the 
  largest 
  

   and 
  most 
  valuable 
  food 
  forms 
  of 
  the 
  oyster 
  — 
  for 
  example, 
  ^ujjodiscus, 
  

   Coscinodiscus, 
  and 
  Melos/ra 
  (see 
  figures, 
  page 
  285); 
  while 
  among 
  the 
  

   last 
  to 
  settle 
  are 
  the 
  light 
  spiny 
  diatoms 
  of 
  which 
  the 
  oyster 
  can 
  make 
  

   no 
  use 
  and 
  of 
  which 
  the 
  water 
  is 
  so 
  full 
  — 
  for 
  example, 
  Nitzschia 
  and 
  

   Rhizosilenia. 
  The 
  former 
  would 
  not 
  be 
  included 
  in 
  the 
  chemical 
  test, 
  

  

  a 
  H. 
  F. 
  Moore: 
  Report 
  on 
  the 
  Oyster 
  Beds 
  of 
  (14) 
  Louisiana. 
  U. 
  S. 
  F. 
  C. 
  Report, 
  1898, 
  pp. 
  45-100. 
  

   & 
  Bashford 
  Dean: 
  " 
  The 
  Physical 
  and 
  Biological 
  Characteristics 
  of 
  the 
  Natural 
  Oyster 
  Grounds 
  of 
  

   South 
  Carolina." 
  Bull. 
  U. 
  S. 
  F. 
  C, 
  1890, 
  pp. 
  335-361. 
  

  

  