﻿PILTEABLB 
  VIRUSES 
  — 
  BOYCOTT 
  333 
  

  

  ister 
  pneumosintes, 
  which 
  is 
  a 
  relative 
  difference 
  of 
  the 
  same 
  order 
  as 
  

   that 
  between 
  a 
  pigmy 
  shrew 
  and 
  a 
  big 
  man 
  or 
  between 
  a 
  laboratory- 
  

   guinea 
  pig 
  and 
  a 
  large 
  elephant. 
  D. 
  pneumosintes 
  is 
  about 
  400 
  times 
  

   the 
  bulk 
  of 
  what 
  we 
  imagine 
  to 
  be 
  an 
  average 
  virus, 
  and 
  if 
  there 
  are 
  no 
  

   large 
  viruses 
  (the 
  organism 
  of 
  cattle 
  pleuropneumonia 
  being 
  prob- 
  

   ably 
  bacillary) 
  there 
  may 
  be 
  more 
  than 
  seems 
  at 
  first 
  sight 
  in 
  our 
  

   definition 
  of 
  the 
  agents 
  we 
  are 
  discussing, 
  by 
  the 
  facts 
  that 
  they 
  

   can 
  not 
  be 
  seen 
  and 
  that 
  they 
  will 
  pass 
  through 
  filters 
  with 
  very 
  small 
  

   holes 
  — 
  a 
  system 
  of 
  classification 
  which 
  has 
  often 
  been 
  laughed 
  at, 
  

   though 
  it 
  could 
  be 
  applied 
  well 
  enough 
  to 
  many 
  animal 
  groups. 
  

  

  Composition. 
  — 
  A 
  diameter 
  of 
  0.025 
  n 
  does 
  not 
  give 
  much 
  room 
  or 
  

   many 
  facilities 
  for 
  complicated 
  vital 
  actions. 
  We 
  do 
  not 
  know 
  what 
  

   occupies 
  that 
  tiny 
  bulk; 
  we 
  do 
  not 
  even 
  know 
  that 
  viruses 
  are 
  mainly 
  

   proteid. 
  There 
  would 
  be 
  room 
  for 
  a 
  larger 
  number 
  of 
  simpler 
  mole- 
  

   cules 
  though 
  it 
  is 
  doubtful 
  whether 
  in 
  any 
  simulacrum 
  of 
  life 
  this 
  

   would 
  compensate 
  for 
  the 
  absence 
  of 
  the 
  unique 
  combination 
  of 
  

   chemical 
  flexibility 
  and 
  physical 
  stability 
  which 
  proteids 
  possess 
  and 
  

   without 
  which, 
  as 
  far 
  as 
  we 
  know, 
  "life" 
  does 
  not 
  exist. 
  The 
  anti- 
  

   genic 
  quality 
  of 
  viruses 
  is 
  our 
  only 
  evidence 
  that 
  they 
  contain 
  proteid. 
  

   Clinically 
  and 
  experimentally 
  they 
  confer 
  a 
  resistance 
  to 
  reinfection 
  

   which 
  is, 
  in 
  comparison 
  with 
  antibacterial 
  immunities, 
  singularly 
  

   intense 
  and 
  durable, 
  and 
  is 
  associated 
  with 
  antiviral 
  properties 
  in 
  the 
  

   blood 
  serum. 
  As 
  against 
  this 
  we 
  have, 
  (1) 
  that 
  antiviral 
  serum 
  con- 
  

   tains 
  only 
  a 
  simple 
  neutralizing 
  principle 
  like 
  an 
  antitoxin 
  (and 
  pos- 
  

   sibly 
  not 
  actually 
  effective 
  in 
  vitro) 
  and 
  has 
  no 
  specific 
  agglutinin 
  

   precipitin 
  or 
  (this 
  is 
  very 
  doubtful) 
  complement-fixing 
  immune 
  body; 
  

   (2) 
  that 
  it 
  is 
  doubtful 
  (though 
  hardly, 
  I 
  think 
  more 
  than 
  that 
  at 
  

   present) 
  whether 
  it 
  is 
  still 
  true 
  to 
  say 
  that 
  all 
  antigens 
  are 
  proteid 
  

   in 
  nature; 
  (3) 
  that 
  substances 
  like 
  diphtheria 
  toxin 
  and 
  the 
  substance 
  

   which 
  Murphy 
  has 
  separated 
  from 
  the 
  Rous 
  sarcoma 
  seem 
  to 
  be 
  pro- 
  

   teids 
  of 
  rather 
  a 
  special 
  and 
  simple 
  kind. 
  Another 
  point 
  which 
  may 
  

   be 
  germane 
  is 
  that 
  the 
  dose 
  of 
  virus 
  used 
  for 
  infection 
  makes 
  much 
  less 
  

   difference 
  in 
  the 
  result 
  than 
  it 
  often 
  does 
  with 
  bacteria. 
  The 
  infective 
  

   units 
  are 
  evidently 
  present 
  in 
  enormous 
  numbers 
  in, 
  e. 
  g., 
  the 
  vesicle 
  

   fluid 
  in 
  foot-and-mouth 
  disease 
  which 
  may 
  be 
  diluted 
  1 
  in 
  10,000,000 
  

   and 
  still 
  carry 
  on 
  infection. 
  There 
  is 
  a 
  minimum 
  infecting 
  dose, 
  

   which 
  shows 
  that 
  infection 
  is 
  due 
  to 
  something 
  definite 
  and 
  not 
  to 
  

   magic, 
  but 
  once 
  this 
  is 
  passed 
  the 
  rate 
  at 
  which 
  the 
  resultant 
  illness 
  

   develops 
  and 
  the 
  degree 
  to 
  which 
  it 
  reaches 
  are 
  not 
  much 
  affected 
  by 
  

   giving 
  1,000 
  or 
  10,000 
  times 
  as 
  much. 
  The 
  big 
  doses 
  of 
  bacteria 
  which 
  

   are 
  often 
  administered 
  to 
  animals 
  contain 
  bacterial 
  substance 
  by 
  whole 
  

   milligrams 
  by 
  which 
  the 
  symptons 
  and 
  course 
  of 
  the 
  infection 
  may 
  be 
  

   greatly 
  influenced. 
  The 
  absence 
  of 
  such 
  poisoning 
  effects 
  with 
  large 
  

   doses 
  of 
  virus 
  may, 
  of 
  course, 
  be 
  due 
  to 
  the 
  smafl 
  quantity 
  of 
  virus 
  

   substance 
  which 
  is 
  given, 
  but 
  it 
  quite 
  possibly 
  follows 
  from 
  its 
  quality. 
  

  

  