﻿TWO 
  DECADES 
  OF 
  GENETIC 
  PROGRESS. 
  

  

  By 
  E. 
  M. 
  East, 
  

   Harvard 
  University, 
  Bussey 
  Institution, 
  Forest 
  Hills, 
  Mass. 
  

  

  Genetics 
  was 
  born 
  21 
  years 
  ago 
  when 
  there 
  came 
  the 
  first 
  real 
  

   appreciation 
  of 
  the 
  studies 
  on 
  heredity 
  made 
  in 
  the 
  little 
  garden 
  at 
  

   Brunn. 
  Now 
  that 
  it 
  has 
  reached 
  full 
  manhood 
  and 
  is 
  ready 
  to 
  as- 
  

   sume 
  the 
  toga 
  virilis, 
  the 
  time 
  seems 
  fitting 
  to 
  call 
  back 
  the 
  yester- 
  

   days, 
  to 
  cast 
  up 
  accounts, 
  and 
  to 
  judge 
  whether 
  the 
  performance 
  of 
  

   maturity 
  promises 
  to 
  repay 
  the 
  cost 
  of 
  infancy 
  and 
  childhood. 
  

  

  Perhaps 
  it 
  will 
  serve 
  our 
  purpose 
  to 
  contrast 
  the 
  status 
  of 
  affairs 
  

   toward 
  the 
  close 
  of 
  the 
  long 
  prenatal 
  period 
  previous 
  to 
  the 
  twentieth 
  

   century 
  with 
  that 
  of 
  to-day. 
  When 
  one 
  does 
  this, 
  he 
  is 
  convinced 
  

   that 
  our 
  chance 
  metaphor 
  is 
  really 
  rather 
  apt. 
  When 
  the 
  chick 
  

   breaks 
  through 
  the 
  egg, 
  when 
  the 
  butterfly 
  bursts 
  the 
  chrysalis, 
  

   when 
  the 
  rosebud 
  opens, 
  the 
  change 
  is 
  superficially 
  so 
  revolutionary 
  

   that 
  one 
  is 
  likely 
  to 
  forget 
  the 
  intensive 
  energy 
  expended 
  in 
  prepara- 
  

   tion 
  for 
  the 
  natal 
  day. 
  So 
  also 
  with 
  the 
  study 
  of 
  heredity. 
  Genetics 
  

   was 
  born 
  and 
  christened 
  because 
  of 
  Gregor 
  Mendel. 
  Not 
  because 
  he 
  

   diligently 
  gathered 
  facts 
  regarding 
  the 
  heredity 
  of 
  the 
  garden 
  pea; 
  

   rather 
  because 
  he 
  was 
  able 
  to 
  analyze 
  and 
  correlate 
  these 
  facts. 
  

   Others 
  had 
  gathered 
  facts 
  galore. 
  Indeed 
  the 
  growth-curve 
  of 
  

   knowledge 
  had 
  been 
  rising 
  steadily 
  for 
  many 
  years. 
  Yet 
  metamor- 
  

   phosis 
  came 
  only 
  when 
  mathematics 
  began 
  to 
  be 
  applied 
  effectively 
  

   to 
  the 
  efforts 
  of 
  physiologist 
  and 
  morphologist. 
  Change 
  in 
  method 
  

   rather 
  than 
  a 
  single 
  great 
  discovery 
  gave 
  the 
  first 
  real 
  insight 
  into 
  the 
  

   master 
  riddle 
  of 
  the 
  ages. 
  

  

  EARLY 
  STUDIES 
  OF 
  HEREDITY. 
  

  

  Previous 
  to 
  the 
  beginning 
  of 
  the 
  twentieth 
  century, 
  isolated 
  ob- 
  

   servations 
  on 
  heredity 
  had 
  been 
  made 
  by 
  many 
  types 
  of 
  workers. 
  It 
  

   was 
  only 
  natural 
  that 
  this 
  should 
  be 
  the 
  case. 
  Such 
  a 
  seemingly 
  

   mysterious 
  force 
  could 
  hardly 
  have 
  failed 
  to 
  fascinate 
  mankind 
  from 
  

   the 
  very 
  beginning 
  of 
  his 
  speculative 
  history. 
  But 
  isolated 
  observa- 
  

   tions 
  on 
  subjects 
  wherein 
  are 
  numerous 
  complex 
  variables 
  usually 
  

  

  1 
  Reprinted 
  by 
  permission, 
  with 
  change 
  of 
  title, 
  from 
  Journal 
  of 
  Heredity, 
  May, 
  1922. 
  

  

  285 
  

  

  