"It requires indeed some courage to undertake a labor of such a far-reaching extent; it appears, however, to be the only right way by which we can finally reach the solution of a question the importance of which cannot be over-estimated in connection with the history of the evolution of organic forms."
He tells us also why he selected peas for his work:
"The selection of the plant group which shall serve for experiments of this kind must be made with all possible care if it be desired to avoid from the outset every risk of questionable results."
"The experimental plants must necessarily
1. Possess constant differentiating characters.
2. The hybrids of such plants must, during the flowering period, be protected from the influence of all foreign pollen, or be easily capable of such protection."
Why do biologists throughout the world to-day agree that Mendel's discovery is one of first rank?
A great deal might be said in this connection. What is essential may be said in a few words. Biology had been, and is still, largely a descriptive and speculative science. Mendel showed by experimental proof that heredity could be explained by a simple mechanism. His discovery has been exceedingly fruitful.
Science begins with naïve, often mystic conceptions of its problems. It reaches its goal whenever it can replace its early guessing by verifiable hypotheses and predictable results. This is what Mendel's law did for heredity.
Mendel's First Discovery—Segregation
Fig. 13. Diagram illustrating a cross between a red (dark) and a white variety of four o'clock (Mirabilis jalapa).