Note 76 — A DEFENCE OF MENDEL’S PRINCIPLES OF HEREDITY.

It will be understood that a “mule” form is quite distinct from what is generally described as a “blend.” One certain criterion of the “mule” form is the fact that it cannot be fixed, see p. 25. There is little doubt that Laxton had such a “mule” form when he speaks of “the remarkably fine but unfixable pea, Evolution.” J. R. Hort. Soc. XII. 1890, p. 37 (v. infra).