﻿542 
  Skvknth 
  Anmal 
  Kepokt 
  of 
  thk 
  

  

  yet 
  developed. 
  It 
  is 
  not 
  yet 
  detennincd 
  how 
  long 
  a 
  tubercle 
  bacil- 
  

   lus 
  may 
  remain 
  on 
  the 
  mucous 
  membrane 
  or 
  in 
  the 
  tissues 
  before 
  

   it 
  begins 
  to 
  multiply, 
  but 
  undoubtedly 
  a 
  number 
  of 
  days 
  may 
  

   intervene. 
  It 
  is 
  not 
  claimed 
  that 
  tuberculin 
  will 
  prodi;c& 
  a 
  reac- 
  

   tion 
  during 
  this 
  period 
  of 
  incubation. 
  On 
  account 
  of 
  th'ese 
  pos- 
  

   sible 
  conditions 
  it 
  may 
  be 
  necessary 
  to 
  apply 
  the 
  test 
  a 
  second 
  or 
  

   even 
  a 
  third 
  time 
  before 
  all 
  traces 
  of 
  the 
  disease 
  can 
  be 
  detected 
  and 
  

   the 
  infected 
  animals 
  removed. 
  

  

  Its 
  use 
  as 
  a 
  protection 
  in 
  introducing 
  new 
  animals 
  has 
  been 
  

   questioned 
  on 
  the 
  ground 
  that 
  a 
  single 
  dose 
  produces 
  immunity, 
  

   so 
  that 
  an 
  unscrupulous 
  owner 
  could 
  protect 
  his 
  animals 
  against 
  

   the 
  legal 
  test. 
  Concerning 
  this 
  point, 
  Dr. 
  Leonard 
  Pearson^' 
  

   writes: 
  " 
  As 
  to 
  the 
  failure 
  of 
  animals 
  to 
  react 
  a 
  second 
  time 
  after 
  

   thev 
  have 
  been 
  tested 
  with 
  tuberculin, 
  I 
  would 
  sav 
  that 
  such 
  a 
  

   failure 
  is 
  distinctly 
  exceptional. 
  Recently 
  a 
  herd 
  of 
  cows 
  was 
  

   tested 
  in 
  Philadelphia 
  by 
  an 
  agent 
  of 
  the 
  city 
  board 
  of 
  health; 
  

   eighteen 
  cows 
  reacted. 
  Tlie 
  herd 
  was 
  tested 
  again 
  within 
  ten 
  

   days 
  by 
  an 
  agent 
  of 
  the 
  Live-Stock 
  Sanitary 
  Board, 
  and 
  the 
  same 
  

   eighteen 
  cows 
  reacted. 
  A 
  double 
  dose 
  of 
  tuberculin 
  was 
  used 
  for 
  

   the 
  second 
  test." 
  Th'e 
  records 
  of 
  repeated 
  injections 
  witliin 
  very 
  

   short 
  periods 
  are 
  not 
  numerous. 
  AVe 
  have 
  already 
  made 
  a 
  few 
  

   such 
  tests 
  and 
  others 
  are 
  in 
  prospect, 
  so 
  that 
  it 
  is 
  hoped 
  that 
  veiy 
  

   soon 
  Ave 
  may 
  have 
  satisfactory 
  data 
  on 
  this 
  point. 
  Three 
  consecu- 
  

   tive 
  injections 
  witliin 
  ten 
  days 
  in 
  a 
  young 
  animal 
  (three 
  months) 
  

   gave 
  a 
  decided 
  reaction 
  each 
  time. 
  The 
  dose 
  was 
  0.25 
  c. 
  c. 
  of 
  

   the 
  diluted 
  tuberculin. 
  A 
  fourth 
  injection 
  failed 
  to 
  give 
  a 
  reac- 
  

   tion. 
  A 
  second 
  case 
  gave 
  like 
  results. 
  A 
  cow 
  failed 
  to 
  react 
  on 
  

   the 
  fourth 
  test. 
  At 
  post-mortem 
  she 
  showed 
  extensive 
  lesions 
  in 
  

   the 
  lungs, 
  mesentery 
  glands, 
  and 
  intestines, 
  and 
  the 
  mucus 
  in 
  the 
  

   throat 
  and 
  trachea 
  contained 
  innumerable 
  tubercle 
  bacilli. 
  N^ocard 
  

   has 
  said 
  that 
  "' 
  about 
  10 
  per 
  cent, 
  of 
  the 
  tubercular 
  cows 
  that 
  re-act 
  

   to 
  the 
  test 
  will 
  fail 
  to 
  react 
  to 
  a 
  second 
  one 
  if 
  it 
  is 
  made 
  within 
  

   one 
  month, 
  and 
  then 
  after 
  each 
  test 
  about 
  10 
  per 
  cent, 
  more 
  will 
  

  

  ISA 
  private 
  letter 
  to 
  the 
  writer 
  bearing 
  date 
  of 
  January 
  4, 
  1900. 
  

  

  