﻿516 
  Seventh 
  Annual 
  Report 
  of 
  the 
  

  

  that 
  a 
  i^athogenic 
  genn 
  which, 
  under 
  given 
  conditions 
  of 
  life, 
  has 
  

   lost 
  in 
  pathogenesis, 
  but 
  not 
  in 
  vitality, 
  should 
  continue 
  forever 
  

   to 
  exist 
  as 
  a 
  harmless 
  mix;roLe. 
  

  

  2. 
  Varying 
  malignancy 
  of 
  the 
  tubercle 
  bacillus 
  in 
  man. 
  

   Nothing 
  is 
  more 
  familiar 
  to 
  physicians 
  than 
  the 
  slow 
  progress 
  of 
  

   tuberculosis 
  of 
  the 
  lymph-glands 
  and 
  bones, 
  on. 
  the 
  one 
  hand, 
  

   and 
  its 
  frequent 
  rapid 
  progress 
  in 
  pulmonary, 
  abdominal, 
  or 
  

   encephalic 
  organs 
  on 
  the 
  other. 
  It 
  has 
  on 
  this 
  account 
  been 
  

   rather 
  difficult 
  to 
  persuade 
  many 
  of 
  the 
  etiological 
  identity 
  of 
  

   scrofula 
  and 
  consumption. 
  In 
  experimental 
  tuberculosis 
  the 
  same 
  

   truth 
  constantly 
  crops 
  up. 
  Arloing 
  and 
  his 
  followers 
  found 
  that 
  

   the 
  tubercle 
  bacillus 
  from 
  the 
  lymph-glands 
  of 
  man 
  proved 
  less 
  

   virulent 
  and 
  deadly 
  than 
  that 
  from 
  the 
  human 
  lungs 
  {Lecons 
  sur 
  

   la 
  Tuberculose). 
  As 
  early 
  as 
  1880, 
  Creighton 
  drew 
  attention 
  to 
  

   this 
  in 
  his 
  work 
  on 
  Bovine 
  Tuberculosis 
  in 
  Man. 
  

  

  But 
  the 
  bacillus 
  from 
  the 
  lungs 
  is 
  subject 
  to 
  such 
  variations. 
  

   Among 
  seven 
  specimens 
  of 
  human 
  sputum 
  cultivated 
  by 
  Theobald 
  

   Smith 
  six 
  had 
  a 
  fair 
  average 
  vitality, 
  while 
  the 
  seventh 
  failed 
  to 
  

   perpetuate 
  itself 
  on 
  dog 
  serum.^ 
  

  

  It 
  should 
  be 
  strongly 
  emphasized 
  in 
  this 
  connection 
  that 
  the 
  

   failure 
  of 
  extension 
  and 
  generalization 
  of 
  the 
  sputum 
  germ 
  when 
  

   transferred 
  to 
  cattle 
  does 
  not 
  distinguish 
  it 
  from 
  the 
  tubercle 
  bacil- 
  

   lus 
  as 
  conveyed 
  from 
  ox 
  to 
  ox. 
  Everyone 
  at 
  all 
  experienced 
  with 
  

   the 
  tuberculin 
  test 
  well 
  knows 
  that 
  in 
  most 
  herds 
  th'e 
  majority 
  of 
  

   the 
  tuberculous 
  animals 
  show 
  no 
  generalization, 
  but 
  only 
  a 
  localized 
  

   tuberculosis. 
  There 
  is 
  reason 
  to 
  believe 
  that 
  even 
  recoveries 
  take 
  

   place 
  after 
  slight 
  infection, 
  and 
  it 
  is 
  certain 
  that 
  many 
  tuberculous 
  

   cattle 
  continue 
  for 
  years 
  in 
  what 
  appears 
  to 
  be 
  good 
  general 
  health. 
  

   Unless 
  in 
  particularly 
  susceptible 
  subjects 
  or 
  under 
  specially 
  poor 
  

   hygienic 
  conditions, 
  or 
  unless 
  in 
  case 
  of 
  reinfection, 
  the 
  average 
  

   bacillus 
  of 
  bovine 
  origin 
  habitually 
  fails 
  to 
  produce 
  in 
  other 
  cattle 
  

   a 
  rapid 
  extension 
  and 
  generalization. 
  

  

  3. 
  Interchangeability 
  of 
  bacillus 
  of 
  man 
  and 
  bird. 
  Of 
  all 
  

   known 
  forms 
  of 
  tubercle 
  bacillus 
  that 
  of 
  birds 
  is 
  the 
  most 
  distant 
  

  

  2 
  Journal 
  of 
  Experimental 
  Medicine, 
  1898, 
  Xo. 
  111. 
  

  

  