HEREDITY 137 



has been suggested that participate inheritance is in 

 reality true alternative inheritance in which the mosaic 

 result is caused by the absence of the factor for uniform- 

 ity. 1 



130. Mendelian inheritance. Progress in the investi- 

 gation of breeding problems has come through statistical 

 investigations, by cytological studies of the germ-cells 

 themselves, and by experimental breeding. Each of 

 these methods has contributed evidence of value in the 

 direction of a more definite understanding of the prin- 

 ciples of heredity. In recent years experimental breeding 

 has contributed very materially to our knowledge of 

 the science of heredity. Improvements in the technique 

 of cell studies has supplemented the results obtained by 

 experimental breeding. It is a significant fact that the 

 hypotheses based upon experimental breeding agree in 

 many important particulars with those derived from 

 minute investigations of the origin and development of 

 'the germ-cells. 



Perhaps the most remarkable series of investigations 

 in experimental breeding were those carried on by Johann 

 Gregor Mendel, an Austrian monk. These interesting 

 investigations gave a new impetus to the study of theoreti- 

 cal heredity and particularly to the practical improve- 

 ment of plants and animals. The investigations of Mendel 

 were first published in 1865 and over twenty years later 

 were again published in the Transactions of the Natural 

 History Society of Briinn. No attention was given to this 

 important contribution to the science of breeding, and 

 even Na'geli, a former teacher of Mendel, to whom the 

 results were submitted, failed to recognize their funda- 

 mental significance. It was not until the year 1900 



1 Walter, "Genetics," p. 164. 



