﻿344 
  James 
  Divight 
  Dana. 
  

  

  2. 
  In 
  the 
  evolution 
  of 
  the 
  animal 
  kingdom 
  a 
  " 
  tendency 
  

   upward" 
  is 
  a 
  necessary 
  consequence 
  of 
  the 
  presence 
  of 
  a 
  ceph- 
  

   alic 
  nervous 
  ganglion 
  or 
  brain. 
  

  

  The 
  theory 
  of 
  evolution, 
  or 
  the 
  development 
  of 
  species, 
  was 
  

   one, 
  as 
  indicated 
  above, 
  that 
  his 
  mind 
  approached 
  slowly. 
  He 
  

   started, 
  like 
  most 
  others, 
  with 
  the 
  belief 
  in 
  the 
  special 
  creation 
  

   of 
  species 
  ; 
  at 
  the 
  same 
  time, 
  his 
  mind 
  even 
  at 
  this 
  period 
  was 
  

   opening 
  out 
  to 
  a 
  broader 
  idea 
  of 
  the 
  relation 
  of 
  species 
  to 
  each 
  

   other. 
  This 
  is 
  hinted 
  at 
  in 
  the 
  closing 
  sentences 
  of 
  the 
  follow- 
  

   ing 
  paragraphs 
  quoted 
  from 
  a 
  chapter 
  on 
  the 
  geographical 
  dis- 
  

   tribution 
  of 
  Crustacea.* 
  

  

  Although 
  we 
  cannot 
  admit 
  that 
  circumstances 
  and 
  

  

  physical 
  forces 
  have 
  ever 
  created 
  a 
  species 
  (as 
  like 
  can 
  only 
  

   beget 
  like 
  and 
  physical 
  force 
  must 
  result 
  simply 
  in 
  physical 
  

   force) 
  and 
  while 
  we 
  see 
  in 
  all 
  nature 
  the 
  free 
  act 
  of 
  the 
  Divine 
  

   Being, 
  we 
  may 
  still 
  believe 
  the 
  connexion 
  between 
  the 
  calling 
  

   into 
  existence 
  of 
  a 
  species 
  and 
  the 
  physical 
  circumstances 
  sur- 
  

   rounding 
  it 
  to 
  be 
  as 
  intimate 
  nearly 
  as 
  cause 
  and 
  effect." 
  

  

  In 
  1857 
  again, 
  in 
  a 
  paper 
  upon 
  Species, 
  published 
  in 
  this 
  

   Journal 
  (vol. 
  xxiv), 
  he 
  says, 
  (p. 
  307, 
  the 
  italics 
  are 
  his) 
  : 
  

  

  A 
  species 
  among 
  living 
  beings, 
  then, 
  as 
  well 
  as 
  inorganic, 
  is 
  

   based 
  on 
  a 
  specific 
  amount 
  or 
  condition 
  of 
  concentered 
  force 
  

   defined 
  in 
  the 
  act 
  or 
  law 
  of 
  creation. 
  

  

  On 
  a 
  later 
  page, 
  he 
  again 
  speaks 
  of 
  a 
  species 
  as 
  " 
  essentially 
  

   permanent 
  or 
  indestructible." 
  

  

  He 
  always 
  maintained, 
  however, 
  that 
  the 
  true 
  scientific 
  spirit 
  

   was 
  to 
  keep 
  the 
  mind 
  open 
  to 
  the 
  reception 
  of 
  new 
  truth, 
  

   even 
  if 
  this 
  was 
  at 
  first 
  opposed 
  to 
  preconceived 
  notions. 
  

   This 
  principle 
  he 
  had 
  exemplified 
  in 
  regard 
  to 
  a 
  subject 
  of 
  

   limited 
  bearings 
  by 
  the 
  change 
  of 
  view 
  on 
  mineralogical 
  

   classification, 
  as 
  is 
  well 
  shown 
  by 
  the 
  quotation 
  from 
  the 
  pre- 
  

   face 
  to 
  his 
  Mineralogy 
  given 
  on 
  a 
  preceding 
  page. 
  And 
  now 
  

   in 
  relation 
  to 
  this, 
  perhaps 
  the 
  broadest 
  generalization 
  in 
  

   science, 
  he 
  was 
  true 
  to 
  this 
  principle 
  again. 
  For 
  gradually, 
  by 
  

   steps 
  that 
  it 
  would 
  be 
  interesting 
  to 
  trace, 
  he 
  came 
  to 
  accept 
  

   very 
  fully 
  the 
  principle 
  of 
  evolution 
  as 
  a 
  fundamental 
  law, 
  

  

  * 
  Report 
  on 
  Crustacea; 
  also 
  this 
  Journal, 
  vol. 
  xx, 
  358, 
  1854. 
  

  

  