I] Rediscovery of Mendel 7 



that order which it was ostensibly undertaken to reveal. 

 A preliminary acquaintance with the natural history of 

 heredity and variation was sufficient to throw doubt on the 

 foundations of these elaborate researches. To those who 

 hereafter may study this episode in the history of biological 

 science it will appear inexplicable that work so unsound in 

 construction should have been respectfully received by the 

 scientific world. With the discovery of segregation it 

 became obvious that methods dispensing with individual 

 analysis" of the material are useless. The only alternatives 

 open to the inventors of those methods were either to 

 abandon their delusion or to deny the truth of Mendclian 

 facts. In choosing the latter course they have certainly 

 succeeded in delaying recognition of the value of Mendelism, 

 but with the lapse of time the number of persons who have 

 themselves witnessed the phenomena has increased so much 

 that these denials have lost their dangerous character and 

 may be regarded as merely formal. 



Rediscovery of Mendel : his Method. 



With the year 1900 a new era begins. In the spring 

 of that year there appeared, within a few weeks of each 

 other, the three papers of de Vries, Correns, and Tschermak, 

 giving the substance of Mendel's long-forgotten treatise. 

 Each of these three writers was able from his own ex- 

 perience to confirm Mendel's conclusions, and to extend 

 them to other cases. There could therefore, from the first, 

 be no question as to the truth of the facts. To appreciate 

 what Mendel did the reader should refer to the original 

 paper^, which is a model of lucidity and expository skill. 

 His success is due to the clearness with which he thought 

 out the problem. Being familiar with the w^orks of Gaertner 

 and the other experimental breeders he surmised that 

 their failure to reach definite and consistent conclusions 

 was due to a want of precise and continued analysis. In 

 order to obtain a clear result he saw that it was absolutely 

 necessary to start with pure-breeding, homogeneous materials, 

 to consider each character separately, and on no account to 

 confuse the different generations together. Lastly he realised 



* See Part II. 



