﻿PILTRABLE 
  VIRUSES 
  BOYCOTT 
  343 
  

  

  why 
  should 
  they 
  have 
  such 
  injurious 
  effects? 
  To 
  which 
  there 
  are 
  two 
  

   answers 
  : 
  First, 
  we 
  apprehend 
  only 
  such 
  disembodied 
  parts 
  of 
  cells 
  as 
  

   produce 
  some 
  definite 
  effect 
  which 
  we 
  can 
  observe, 
  and, 
  as 
  it 
  happens 
  

   we 
  have 
  perceived 
  only 
  those 
  which 
  do 
  damage; 
  second, 
  believing 
  as 
  

   the 
  fundamental 
  proposition 
  of 
  morbid 
  anatomy 
  that 
  structure 
  and 
  

   function 
  go 
  hand 
  in 
  hand, 
  we 
  should 
  naturally 
  expect 
  such 
  gross 
  aber- 
  

   ration 
  of 
  structure 
  to 
  result 
  in 
  such 
  a 
  departure 
  from 
  the 
  normal 
  course 
  

   of 
  function 
  as, 
  in 
  this 
  so 
  nicely 
  adapted 
  world, 
  would 
  manifest 
  itself 
  

   as 
  injurious. 
  

  

  What 
  to 
  make 
  of 
  all 
  this 
  confused 
  mass 
  of 
  facts 
  and 
  speculation 
  I 
  do 
  

   not 
  know. 
  We 
  seem 
  to 
  have 
  a 
  fairly 
  definite 
  group 
  of 
  things 
  which, 
  

   (a) 
  are 
  very 
  small; 
  (b) 
  can 
  multiply; 
  (c) 
  have 
  no 
  independent 
  life; 
  (d) 
  

   are 
  of 
  uncertain 
  origin. 
  Of 
  their 
  multiplication 
  we 
  know 
  that 
  the 
  

   association 
  of 
  live 
  cells 
  is 
  necessary, 
  and 
  that 
  it 
  occurs 
  when 
  the 
  specific 
  

   effect 
  of 
  the 
  agent 
  is 
  manifested; 
  we 
  do 
  not 
  know 
  that 
  direct 
  multipli- 
  

   cation 
  is 
  possible 
  at 
  all. 
  Of 
  their 
  origin, 
  we 
  have 
  strong 
  grounds 
  for 
  

   thinking 
  that 
  some 
  are 
  derived 
  from 
  live 
  cells 
  and 
  we 
  can 
  not 
  exclude 
  

   this 
  ancestry 
  for 
  any 
  of 
  them. 
  They 
  seem, 
  too, 
  to 
  form 
  a 
  series: 
  

   (1) 
  The 
  growth-promoting 
  substances 
  from 
  tissues 
  show 
  indirect 
  mul- 
  

   tiplication 
  but 
  make 
  no 
  other 
  suggestion 
  of 
  life; 
  (2) 
  lysozyme 
  would 
  

   pass 
  for 
  an 
  enzyme 
  except 
  that 
  it 
  can 
  multiply; 
  (3) 
  the 
  Kous 
  agent 
  

   and 
  the 
  bacteriophage 
  arise 
  repeatedly 
  in 
  malignant 
  tumors 
  and 
  bac- 
  

   teria, 
  respectively, 
  and 
  may 
  be 
  in 
  some 
  sense 
  alive, 
  but 
  they 
  are 
  not 
  

   independent 
  species 
  of 
  animals 
  or 
  plants; 
  (4) 
  the 
  pathogenic 
  viruses 
  

   represent 
  a 
  further 
  step 
  toward 
  being 
  wholly 
  alive. 
  Taking 
  one 
  thing 
  

   with 
  another, 
  I 
  am 
  inclined 
  to 
  think 
  that 
  they 
  are 
  both 
  the 
  cause 
  and 
  

   the 
  result 
  of 
  their 
  diseases 
  as 
  Sanfelice 
  suggested 
  for 
  epithelioma 
  con- 
  

   tagiosum. 
  Somehow 
  or 
  other 
  a 
  virus 
  arises 
  in 
  an 
  animal 
  or 
  plant 
  and 
  

   by 
  its 
  action 
  on 
  the 
  tissues 
  causes 
  them 
  to 
  produce 
  more 
  of 
  itself. 
  Some 
  

   viruses 
  (e. 
  g., 
  smallpox) 
  acquire 
  a 
  considerable 
  capacity 
  of 
  spreading 
  

   from 
  infected 
  to 
  normal 
  individuals 
  and 
  the 
  majority 
  of 
  cases 
  of 
  the 
  

   disease 
  are 
  so 
  caused; 
  the 
  virus 
  is 
  on 
  the 
  way 
  toward 
  independence. 
  

   Others 
  (e. 
  g., 
  herpes) 
  have 
  little 
  or 
  no 
  power 
  of 
  dispersion 
  and 
  most 
  

   cases 
  are 
  due 
  to 
  the 
  virus 
  arising 
  de 
  novo 
  under 
  the 
  appropriate 
  stimu- 
  

   lus 
  (whatever 
  that 
  may 
  be). 
  You 
  may 
  say 
  that 
  if 
  that 
  is 
  so 
  it 
  is 
  

   strange 
  that 
  one 
  case 
  of 
  herpes 
  is 
  so 
  like 
  another 
  and 
  that 
  epidemic 
  

   virus 
  diseases 
  are 
  so 
  uniform 
  in 
  their 
  characters 
  and 
  so 
  "true 
  to 
  type." 
  

   It 
  is, 
  indeed, 
  rather 
  curious, 
  but 
  the 
  circumstances 
  which 
  lead 
  to 
  the 
  

   generation 
  of 
  a 
  virus 
  are 
  presumably 
  often 
  repeating 
  themselves, 
  the 
  

   possibilities 
  of 
  parts 
  of 
  cells 
  having 
  a 
  separate 
  existence 
  are 
  very 
  likely 
  

   limited, 
  and 
  after 
  all 
  the 
  specific 
  characters 
  of 
  infectious 
  diseases 
  are 
  

   not 
  always 
  very 
  sharply 
  defined. 
  However, 
  these 
  are 
  difficulties 
  which 
  

   I 
  am 
  not 
  prepared 
  to 
  solve; 
  my 
  object 
  has 
  been 
  to 
  ask 
  questions 
  rather 
  

   than 
  to 
  answer 
  them. 
  

  

  I 
  have 
  made 
  no 
  attempt 
  to 
  acknowledge 
  the 
  many 
  sources, 
  printed 
  

   and 
  verbal, 
  from 
  which 
  I 
  have 
  derived 
  facts 
  and 
  ideas. 
  

  

  