﻿THE 
  EVIDENCE 
  BEARING 
  ON 
  MAN'S 
  EVOLUTION 
  

  

  By 
  Ale§ 
  Hrdli(::ka 
  

  

  What 
  is 
  the 
  actual, 
  precise, 
  evidence 
  of 
  human 
  evolution 
  that 
  

   science 
  now 
  possesses, 
  and 
  upon 
  which 
  it 
  bases 
  its 
  far-reaching 
  

   conclusions 
  ? 
  

  

  Since 
  the 
  Dayton 
  trial 
  this 
  question 
  has 
  more 
  or 
  less 
  been 
  dealt 
  

   with 
  in 
  many 
  writings. 
  In 
  the 
  United 
  States 
  alone 
  more 
  has 
  been 
  

   published 
  on 
  the 
  subject 
  since 
  1925 
  than 
  in 
  all 
  the 
  time 
  previous, 
  and 
  

   incomparably 
  more 
  has 
  been 
  read. 
  Yet 
  there 
  are 
  many 
  calls 
  for 
  

   further 
  statements, 
  for 
  simply 
  and 
  comprehensively 
  presented 
  facts 
  

   that 
  would 
  carry 
  no 
  plea, 
  no 
  argument, 
  and 
  that 
  could 
  safely 
  be 
  

   accepted. 
  

  

  To 
  thus 
  present 
  the 
  subject 
  is 
  not 
  easy. 
  Its 
  scope 
  is 
  large. 
  It 
  

   involves 
  many 
  branches 
  of 
  knowledge, 
  biological, 
  physical, 
  and 
  

   chemical. 
  For 
  man 
  possesses 
  not 
  merely 
  form 
  and 
  his 
  faculties, 
  but 
  

   he 
  is 
  at 
  the 
  same 
  time 
  a 
  highly 
  complex 
  chemical 
  and 
  dynamic 
  

   machine. 
  To 
  properly 
  deal 
  with 
  all 
  this 
  would 
  require 
  a 
  large 
  

   treatise. 
  Nevertheless 
  something 
  of 
  an 
  abstract 
  of 
  what 
  is 
  known 
  

   in 
  these 
  lines 
  is 
  possible 
  and 
  may 
  be 
  of 
  service. 
  

  

  That 
  part 
  of 
  the 
  evidence 
  of 
  man's 
  evolution 
  which 
  is 
  regarded 
  as 
  

   already 
  fairly 
  well 
  established 
  may 
  be 
  subdivided 
  as 
  follows 
  : 
  

  

  A. 
  THE 
  INDIRECT 
  EVIDENCE 
  

  

  1. 
  Analogies 
  in 
  inorganic 
  nature. 
  

  

  2. 
  Evolution 
  in 
  all 
  known 
  organic 
  forms. 
  

  

  3. 
  Man's 
  appearance 
  on 
  the 
  earth 
  at 
  the 
  right 
  time 
  of 
  organic 
  

   advance. 
  

  

  B. 
  THE 
  DIRECT 
  EVIDENCE 
  

  

  1. 
  Relation 
  of 
  various 
  structures 
  in 
  the 
  embryonic 
  development 
  of 
  

   man 
  to 
  those 
  represented 
  by 
  some 
  lower 
  vertebrates. 
  

  

  2. 
  Similarities 
  with 
  other 
  mammals 
  in 
  mode 
  of 
  conception, 
  proc- 
  

   esses 
  of 
  development, 
  in 
  all 
  vital 
  functions, 
  in 
  the 
  whole 
  life 
  course, 
  

   in 
  senescence 
  when 
  continuation 
  of 
  the 
  kind 
  is 
  assured, 
  and 
  in 
  death. 
  

  

  3. 
  Physical 
  similarities 
  to 
  identities 
  in 
  organs, 
  limbs, 
  and 
  all 
  other 
  

   physical 
  as 
  well 
  as 
  microscopic 
  parts 
  of 
  the 
  human 
  body. 
  

  

  417 
  

  

  