﻿392 
  PROFESSOR 
  ALISON'S 
  DEFENCE 
  

  

  of 
  a 
  more 
  refined 
  and 
  subtle 
  description 
  than 
  any 
  which 
  we 
  can 
  command, 
  and 
  

   may 
  therefore 
  accomplish 
  effects 
  by 
  purely 
  chemical 
  and 
  physical 
  agency, 
  which 
  

   may 
  for 
  ever 
  lie 
  beyond 
  the 
  reach 
  of 
  the 
  coarser 
  manipulations 
  of 
  art 
  ; 
  and 
  here 
  

   he 
  refers 
  to 
  Humboldt, 
  who 
  says, 
  that, 
  as 
  we 
  do 
  not 
  understand 
  all 
  the 
  conditions 
  

   under 
  which 
  ordinary 
  chemical 
  and 
  physical 
  forces 
  act 
  in 
  living 
  beings, 
  we 
  are 
  

   not 
  entitled 
  to 
  assert 
  that 
  they 
  may 
  not 
  produce 
  all 
  the 
  chemical 
  changes 
  that 
  we 
  

   see 
  in 
  them 
  : 
  to 
  what 
  conditions 
  he 
  here 
  alludes 
  does 
  not 
  appear, 
  but 
  he 
  gives 
  this 
  

   as 
  a 
  reason 
  for 
  renouncing, 
  or, 
  at 
  least, 
  expressing 
  doubts 
  as 
  to 
  the 
  theory 
  of 
  

   vital 
  affinity, 
  which 
  he 
  had 
  formerly 
  espoused, 
  and 
  illustrated 
  by 
  an 
  allegory 
  

   under 
  the 
  name 
  of 
  the 
  Rhodian 
  Genius. 
  

  

  Dr 
  Daubeny 
  says 
  more 
  precisely, 
  that 
  " 
  the 
  peculiar 
  structure 
  of 
  parts, 
  arising 
  

   out 
  of 
  the 
  Movements 
  induced 
  by 
  a 
  vital 
  principle, 
  may 
  be 
  found 
  competent 
  to 
  

   bring 
  about 
  these 
  phenomena 
  in 
  question, 
  and 
  that 
  it 
  is 
  incumbent 
  on 
  us 
  to 
  in- 
  

   vestigate 
  to 
  the 
  full 
  the 
  extent 
  to 
  which 
  such 
  physical 
  causes 
  can 
  be 
  supposed 
  to 
  

   operate, 
  before 
  pronouncing 
  whether 
  there 
  may 
  not, 
  after 
  all, 
  be 
  some 
  residual 
  

   phenomenon, 
  inexplicable 
  by 
  the 
  common 
  principles 
  of 
  science, 
  and 
  which 
  we 
  must, 
  

   therefore, 
  refer 
  to 
  vital 
  affinity." 
  But 
  even 
  in 
  regard 
  to 
  movements, 
  from 
  his 
  ex- 
  

   pressions 
  at 
  p. 
  379, 
  he 
  does 
  not 
  seem 
  to 
  admit 
  that 
  any 
  others 
  are 
  to 
  be 
  ascribed 
  

   to 
  the 
  vital 
  principle, 
  than 
  those 
  which 
  result 
  from 
  Contractility. 
  

  

  In 
  thus 
  admitting 
  that 
  the 
  movements 
  which 
  take 
  place 
  in 
  living 
  animals, 
  at 
  

   least 
  those 
  which 
  can 
  be 
  referred 
  to 
  contraction 
  of 
  solids, 
  arise 
  out 
  of 
  the 
  vital 
  

   principle 
  (which, 
  I 
  apprehend, 
  means 
  only 
  that 
  they 
  are 
  an 
  ultimate 
  fact, 
  — 
  so 
  

   far 
  as 
  yet 
  known 
  exemplified 
  in 
  no 
  other 
  department 
  of 
  nature) 
  ; 
  and 
  in 
  as- 
  

   cribing 
  to 
  the 
  peculiarity 
  of 
  those 
  movements 
  the 
  peculiar 
  structure 
  of 
  living 
  

   parts, 
  and 
  through 
  the 
  intervention 
  of 
  that 
  structure 
  the 
  peculiar 
  chemical 
  changes 
  

   of 
  living 
  beings, 
  Dr 
  Daubeny 
  has 
  stated 
  what 
  I 
  believe 
  to 
  be 
  the 
  general 
  idea 
  of 
  

   those 
  physiologists 
  who 
  reject 
  the 
  doctrine 
  of 
  vital 
  affinity. 
  They 
  think 
  that 
  

   having 
  allowed 
  that 
  movements, 
  and 
  particularly 
  contractions 
  of 
  living 
  solids, 
  are 
  

   truly 
  vital 
  phenomena, 
  they 
  have 
  furnished 
  a 
  possible 
  explanation 
  of 
  all 
  chemical 
  

   changes 
  which 
  seem 
  peculiar 
  to 
  life, 
  and 
  that 
  they 
  are 
  entitled 
  to 
  throw 
  on 
  us 
  the 
  

   burden 
  of 
  disproving 
  this 
  theory, 
  before 
  they 
  can 
  be 
  called 
  on 
  to 
  admit 
  any 
  such 
  

   principle 
  as 
  vital 
  affinity 
  modifying 
  chemical 
  laws 
  in 
  the 
  living 
  body. 
  

  

  To 
  this 
  I 
  reply, 
  first, 
  that 
  this 
  theory 
  in 
  explanation 
  of 
  the 
  chemical 
  pheno- 
  

   mena 
  of 
  life 
  is 
  distinctly 
  inadequate. 
  I 
  do 
  not 
  think 
  it 
  can 
  be 
  more 
  distinctly 
  

   stated, 
  or 
  more 
  plausibly 
  supported, 
  than 
  it 
  was 
  by 
  the 
  late 
  Dr 
  Murray, 
  in 
  treat- 
  

   ing 
  of 
  Secretion, 
  who, 
  at 
  the 
  same 
  time, 
  however, 
  distinctly 
  admitted 
  that 
  it 
  was 
  

   " 
  hypothesis 
  supported 
  by 
  little 
  direct 
  proof. 
  The 
  cause 
  of 
  production 
  of 
  the 
  new 
  

   combinations 
  which 
  constitute 
  secretion," 
  he 
  says, 
  " 
  may 
  be 
  the 
  simple 
  approxima- 
  

   tion 
  of 
  the 
  elements 
  which 
  constitute 
  the 
  blood. 
  That 
  fluid 
  is 
  propelled 
  byt 
  he 
  vis 
  

   a 
  tergo 
  into 
  canals 
  of 
  the 
  most 
  astonishing 
  minuteness, 
  the 
  diameters 
  of 
  which 
  are 
  

  

  