﻿Commissioner 
  of 
  Agricultuke. 
  545 
  

  

  remarks 
  on 
  tliis 
  topic. 
  The 
  most 
  I 
  can 
  hope 
  to 
  do, 
  however, 
  is 
  to 
  

   call 
  attention 
  to 
  the 
  results 
  of 
  certain 
  investigations 
  Avhich 
  have 
  

   enlightened 
  us 
  on 
  this 
  subject, 
  and 
  which, 
  unfortunately, 
  have 
  been 
  

   charged 
  with 
  proving 
  the 
  specific 
  distinction 
  of 
  these 
  organisms. 
  

  

  From 
  the 
  time 
  of 
  the 
  discovery 
  of 
  the 
  tubercle 
  bacillus 
  in 
  man 
  

   and 
  the 
  lower 
  animals 
  until 
  quite 
  recently 
  it 
  was 
  generally 
  believed, 
  

   and 
  so 
  asserted 
  by 
  the 
  authorities 
  on 
  this 
  subject, 
  that 
  the 
  bacilli 
  

   from 
  different 
  species 
  of 
  mammals 
  were 
  identical. 
  It 
  was 
  not, 
  I 
  

   think, 
  until 
  Smith's 
  publications^^ 
  that 
  doubts 
  of 
  a 
  serious 
  nature 
  

   have 
  arisen 
  concerning 
  the 
  validity 
  of 
  these 
  statements. 
  The 
  

   former 
  opinions 
  were 
  based 
  largely 
  on 
  the 
  similarity 
  in 
  their 
  gen- 
  

   eral 
  morphological 
  characters, 
  microchemical 
  reactions, 
  and 
  the 
  

   similaiity 
  in 
  their 
  pathogenesis 
  for 
  the 
  susceptible 
  guinea-pig. 
  Con- 
  

   trary 
  to 
  the 
  general 
  belief, 
  the 
  cultivation 
  of 
  tubercle 
  bacilli 
  from 
  

   tuberculous 
  lesions 
  in 
  cattle 
  or 
  other 
  animals 
  has 
  been 
  a 
  very 
  diffi- 
  

   cult 
  task. 
  To 
  obtain 
  pure 
  cultures 
  of 
  tubercle 
  bacilli 
  directly 
  from 
  

   tuberculous 
  lesions 
  was 
  the 
  fortune 
  of 
  but 
  few 
  bacteriologists 
  until 
  

   the 
  development 
  of 
  the 
  present 
  meth'od 
  of 
  isolating 
  them, 
  which 
  

   was 
  formulated 
  and 
  published 
  by 
  Theobald 
  Smith,^ 
  in 
  1898. 
  

   Since 
  that 
  time 
  more 
  attention 
  has 
  been 
  given 
  to 
  this 
  subject, 
  and 
  a 
  

   comparative 
  study 
  of 
  tubercle 
  bacilli 
  from 
  different 
  sources, 
  espe- 
  

   cially 
  from 
  cattle 
  and 
  man, 
  is 
  being 
  made 
  in 
  a 
  number 
  of 
  labora- 
  

   tories. 
  We 
  have 
  reason 
  to 
  expect, 
  therefore, 
  that 
  within 
  the 
  next 
  

   few 
  years 
  much 
  new 
  information 
  concerning 
  these 
  organisms 
  will 
  be 
  

   forthconiing. 
  

  

  At 
  the 
  present 
  moment 
  most 
  of 
  our 
  knowledge 
  on 
  the 
  subject 
  of 
  

   varieties 
  or 
  races 
  of 
  tubercle 
  bacilli 
  is 
  contained 
  in 
  the 
  papers 
  by 
  

   Theobald 
  Smith. 
  The 
  high 
  character 
  of 
  the 
  work 
  precludes 
  the 
  

   further 
  unqualified 
  acceptance 
  of 
  the 
  former 
  theory 
  of 
  the 
  identity 
  

   of 
  tubercle 
  bacilli, 
  but 
  it' 
  does 
  not 
  warrant 
  the 
  acceptance 
  of 
  tlie 
  

   assertion, 
  which 
  those 
  unfamiliar 
  with 
  such' 
  work 
  have 
  made, 
  tliat 
  

  

  19 
  (1) 
  Transactions 
  of 
  the 
  Association 
  of 
  American 
  Physicians, 
  ]896, 
  vol. 
  

   xi, 
  p. 
  37. 
  (2) 
  Annual 
  Report 
  of 
  the 
  Bureau 
  of 
  Animal 
  Industry, 
  1895-18iHi 
  

  

  (published 
  early 
  in 
  1897). 
  (3) 
  Journal 
  of 
  Experimental 
  Medicine, 
  1898, 
  vol, 
  

   iii, 
  p. 
  451. 
  

  

  20 
  Journal 
  of 
  Experimental 
  Medicine, 
  1898, 
  vol. 
  iii, 
  p. 
  451. 
  

  

  c;5 
  

  

  