"Investigations that before had only been imagined as desirable now became easy to pursue, and questions as to the genetic inter-relations and compositions of varieties can now be definitely answered. Without prejudice to what the future may disclose whether by way of limitation or extension of the Mendelian method, it can be declared with confidence and certainty that we have now the means of beginning an analysis of living organisms, and distinguishing many of the units or factors which essentially determine and cause the development of their several attributes. Briefly put, the essence of the Mendelian lies in the discovery of the existence of unit characters or factors."
January 1, 1970
https://en.wikiquote.org/wiki/Gregor_Mendel