﻿420 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  other 
  animals, 
  flints 
  that 
  show 
  intentional, 
  objective 
  chipping. 
  Some 
  

   creature 
  has 
  developed 
  " 
  hands," 
  full 
  fledged 
  enough 
  to 
  do 
  the 
  chip- 
  

   jiing 
  and 
  to 
  use 
  the 
  resulting 
  tools 
  or 
  weapons, 
  with 
  mentality 
  enough 
  

   behind 
  them 
  to 
  appreciate 
  the 
  advantage 
  of 
  such 
  artifacts 
  as 
  well 
  as 
  

   to 
  make 
  them 
  and 
  use 
  them 
  for 
  definite 
  purposes. 
  There 
  is 
  a 
  new 
  

   form 
  of 
  existence, 
  a 
  beginning 
  of 
  beings 
  with 
  enough 
  mentality 
  to 
  

   advance 
  to 
  " 
  cultural 
  " 
  manifestations. 
  From 
  which 
  time 
  on 
  evi- 
  

   dence 
  of 
  these 
  new 
  beings 
  never 
  lapses, 
  but 
  in 
  general 
  augments 
  step 
  

   by 
  step, 
  extending 
  over 
  many 
  lands. 
  The 
  artifacts 
  keep 
  on 
  develop- 
  

   ing 
  in 
  workmanship 
  and 
  variety, 
  until, 
  well 
  before 
  the 
  middle 
  of 
  the 
  

   ice 
  age, 
  they, 
  reach 
  a 
  status 
  that 
  is 
  clearly 
  " 
  human." 
  There 
  has 
  

   definitely 
  come 
  into 
  being 
  a 
  Man. 
  

  

  In 
  all 
  this 
  there 
  is 
  a 
  logical 
  and 
  orderly 
  sequence 
  which, 
  of 
  neces- 
  

   sity, 
  must 
  be 
  given 
  great 
  weight 
  in 
  the 
  studies 
  of 
  man's 
  origin. 
  

  

  EMBRYOLOGIOAL 
  EVIDENCE 
  

  

  The 
  human 
  being 
  begins 
  with 
  two 
  minute 
  " 
  germ 
  " 
  cells, 
  that 
  

   come 
  from 
  the 
  two 
  " 
  sexes," 
  and 
  that 
  have 
  to 
  unite 
  into 
  one 
  unit, 
  

   which 
  then 
  divides, 
  grows, 
  and 
  develops 
  in 
  most 
  intricate 
  ways, 
  all 
  

   precisely 
  as 
  in 
  the 
  case 
  of 
  any 
  other 
  vertebrate. 
  This 
  beginning 
  of 
  

   the 
  new 
  being, 
  and 
  the 
  following 
  stages 
  of 
  embryonal 
  development, 
  

   constitute 
  an 
  array 
  of 
  conditions 
  and 
  processes 
  so 
  minute, 
  and 
  so 
  

   important, 
  and 
  so 
  thoroughly 
  regulated, 
  that 
  they 
  could 
  never 
  be 
  

   duplicated 
  accidentally. 
  To 
  the 
  student 
  with 
  the 
  microscope 
  the 
  or- 
  

   ganic 
  unity 
  of 
  man 
  with 
  the 
  rest 
  of 
  the 
  living 
  beings, 
  and 
  especially 
  

   with 
  the 
  rest 
  of 
  the 
  mammals, 
  is 
  indeed 
  a 
  profound 
  fact, 
  a 
  fact 
  so 
  

   plain 
  and 
  complete 
  and 
  great 
  that 
  to 
  the 
  scientist 
  it 
  alone 
  is 
  wholly 
  

   sufficient 
  for 
  a 
  conviction 
  of 
  unity. 
  Even 
  heredity, 
  that 
  vastly 
  com- 
  

   plex 
  endowment 
  of 
  every 
  organism, 
  is 
  now 
  known 
  to 
  be 
  carried 
  by 
  

   like 
  clusters 
  of 
  molecules, 
  known 
  as 
  " 
  chromosomes 
  " 
  and 
  " 
  genes," 
  

   in 
  each 
  germ 
  cell, 
  human 
  or 
  animal. 
  

  

  In 
  addition, 
  the 
  human 
  embryo 
  shows 
  at 
  various 
  stages 
  traces 
  of 
  

   prehuman 
  characteristics 
  that 
  disappear 
  or 
  are 
  reduced 
  to 
  rudi- 
  

   mentary 
  condition 
  in 
  the 
  course 
  of 
  subsequent 
  development. 
  These 
  

   matters 
  are 
  too 
  technical 
  for 
  a 
  general 
  discussion, 
  but 
  features 
  that 
  

   may 
  be 
  mentioned 
  are 
  the 
  initial 
  primitiveness 
  of 
  the 
  neck, 
  hands, 
  

   and 
  feet; 
  the 
  rudimentary 
  tvV^jsvhich 
  persists 
  in 
  the 
  human 
  embryo 
  

   up 
  to 
  and 
  even 
  over 
  the 
  ninin 
  week 
  of 
  prenatal 
  age; 
  the 
  early 
  hair 
  

   covering 
  the 
  body 
  and 
  face 
  ; 
  the 
  presence 
  of 
  plain 
  traces 
  of 
  the 
  inter- 
  

   maxillary 
  bone; 
  the 
  at 
  first 
  birdlike, 
  entirely 
  smooth 
  brain. 
  These 
  

   and 
  other 
  similar 
  features, 
  taken 
  together, 
  are 
  so 
  impressive 
  that 
  

   the 
  human 
  embryonal 
  period 
  has 
  been 
  called 
  the 
  period 
  of 
  " 
  recapitu- 
  

   lation 
  " 
  of 
  evolution. 
  

  

  