CHAPTER XV 

 MENDELIAN HEREDITY 



Johann Gregor Mendel, an Austrian monk, is the greatest figure 

 in the history of genetics. With less formal training in biology 

 than many college graduates of today he was destined through 

 his keen powers of analysis and his painstaking experimental 

 methods to give the world the first valualjle laws of transmission 

 of characters through heredity. These laws have stood the test 

 of years and have been proved over and over again by the 

 researches of the twentieth century. Cytological studies have 

 established with reasonable certainty the physical foundation for 

 them, and they now form an accepted basis for the usual procedure 

 of genetic investigation. 



Mendel's work was carried on in the peaceful atmosphere of 

 his monastery garden at Briinn, where experiments covering 

 many years led at last to the formulation of the laws that bear 

 his name. His results were presented to the Natural History 

 Society of Briinn and in 1866 appeared in the transactions of 

 that society. They were then lost to the scientific world until 

 1900, perhaps l^ecause of the obscurity of the publication and 

 perhaps because the world was not ready to receive them. Both 

 causes have been suggested and both are probably true. 



In 1900 three scientists are said to have revived Mendel's paper 

 independently. They were De Vries of Holland, Correns of Ger- 

 many and Tschermak of Austria. Suffice it to say that dis- 

 coveries in which these men participated disclosed the sound 

 value of Mendel's pioneer work and it became an accepted part 

 of science. The succeeding quarter of a century has witnessed a 

 constant increase in contributions to genetics, of which practically 

 all are based on Mendel's laws. Mendel himself, like so many dis- 

 tinguished men, died long before his work was recognized, in 1884. 



Mendel's Materials. The variable characters of garden peas 

 constituted the material used by Mendel. These plants lent 

 themselves equally well to crossbreeding and inbreeding, they 

 were easy to raise under cultivation without forcing a change 



27G 



