﻿ORGANISM 
  AND 
  MECHANISM 
  127 
  

  

  When 
  we 
  take 
  the 
  most 
  familiar 
  case 
  of 
  all, 
  the 
  development 
  

   of 
  the 
  chick 
  in 
  the 
  course 
  of 
  twenty-one 
  days 
  from 
  a 
  minute 
  

   drop 
  of 
  living 
  matter 
  lying 
  on 
  the 
  top 
  of 
  the 
  yolk 
  the 
  

   gradual 
  emergence 
  of 
  the 
  obviously 
  complex 
  from 
  the 
  ap- 
  

   parently 
  simple 
  we 
  feel 
  how 
  true 
  it 
  is 
  still, 
  what 
  Harvey 
  

   wrote 
  three 
  centuries 
  ago 
  : 
  " 
  Neither 
  the 
  schools 
  of 
  physi- 
  

   cians 
  nor 
  Aristotle's 
  discerning 
  brain 
  have 
  disclosed 
  the 
  man- 
  

   ner 
  how 
  the 
  cock 
  and 
  its 
  seed 
  doth 
  mint 
  and 
  coin 
  the 
  chicken 
  

   out 
  of 
  the 
  egg." 
  It 
  is 
  not 
  surprising 
  that 
  the 
  facts 
  of 
  genera- 
  

   tion 
  and 
  development 
  have 
  often 
  led 
  naturalists 
  to 
  the 
  con- 
  

   clusion 
  that 
  the 
  categories 
  of 
  mechanism 
  fall 
  short 
  in 
  the 
  

   domain 
  of 
  the 
  organic. 
  What 
  particular 
  facts 
  of 
  devel- 
  

   opment 
  seem 
  to 
  require 
  more 
  than 
  mechanical 
  description 
  ? 
  

   There 
  is 
  the 
  condensation 
  of 
  the 
  inheritance 
  into 
  the 
  micro- 
  

   scopically 
  minute 
  germ-cell 
  an 
  extraordinary 
  telescoping 
  of 
  

   individuality, 
  of 
  which 
  we 
  can 
  form 
  no 
  image. 
  It 
  is 
  quite 
  

   true 
  that 
  there 
  is 
  within 
  egg-cells 
  a 
  demonstrable 
  complexity 
  

   of 
  organisation 
  far 
  greater 
  than 
  used 
  to 
  be 
  supposed, 
  that 
  

   the 
  nucleus 
  is 
  a 
  little 
  world 
  in 
  itself, 
  that 
  there 
  is 
  a 
  

   growing 
  knowledge 
  of 
  extremely 
  minute, 
  yet 
  often 
  distinc- 
  

   tive, 
  organ-forming 
  plastosomes 
  in 
  the 
  cytoplasm 
  of 
  the 
  egg, 
  

   that 
  the 
  artificial 
  removal 
  of 
  part 
  of 
  the 
  egg-cell 
  is 
  sometimes, 
  

   as 
  in 
  Ascidians, 
  followed 
  by 
  the 
  non-development 
  of 
  a 
  partic- 
  

   ular 
  structure 
  in 
  the 
  embryo, 
  and 
  so 
  on. 
  More 
  and 
  more 
  

   we 
  are 
  coming 
  to 
  see 
  in 
  the 
  germ-cell 
  an 
  implicit 
  individ- 
  

   uality 
  with 
  complex 
  and 
  specific 
  organisation. 
  But 
  no 
  sooner 
  

   have 
  we 
  got 
  this 
  idea 
  clearly 
  focused 
  in 
  the 
  mind 
  than 
  we 
  

   are 
  confronted 
  with 
  such 
  facts 
  as 
  those 
  of 
  merogony, 
  that 
  

   a 
  fragment 
  of 
  an 
  egg-cell 
  is 
  able 
  to 
  develop 
  into 
  a 
  normal 
  

   embryo. 
  It 
  may 
  be 
  an 
  argumentum 
  ad 
  ignoraniiam, 
  but 
  

   if 
  it 
  be 
  held, 
  as 
  the 
  mechanists 
  hold, 
  that 
  the 
  egg-cell 
  is 
  

   completely 
  describable 
  as 
  a 
  chernico-physical 
  mechanism 
  of 
  

  

  