[76] 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_). This conception of the “mule” form, or “hybrid-character” as Mendel called it, though undeveloped, is perfectly clear in his work. He says that the dominant character may have two significations, it may be either a parental character or a hybrid-character, and it must be differentiated according as it appears in the one capacity or the other. He does not regard the character displayed by the hybrid, whether dominant or other, _as a thing inherited from or transmitted by the pure parent at all, but as the peculiar function or property of the hybrid_. When this conception has been fully understood and appreciated in all its bearings it will be found to be hardly less fruitful than that of the purity of the germ-cells. The two parents are two--let us say--substances[77] represented by corresponding gametes. These gametes unite to form a new “substance”--the cross-bred zygote. This has its own properties and structure, just as a chemical compound has, and the properties of this new “substance” are _not more strictly_ traceable to, or “inherited” from, those of the two parents than are those of a new chemical compound “inherited” from those of the component elements. If the case be one in which the gametes are pure, the new “substance” is not represented by them, but the compound is again dissociated into its components, each of which is separately represented by gametes. [77] Using the word metaphorically. The character of the cross-bred zygote may be anything. It may be something we have seen before in one or other of the parents, it may be intermediate between the two, or it may be something new. All these possibilities were known to Mendel and he is perfectly aware that his principle is equally applicable to all. The first case is his “dominance.” That he is ready for the second is sufficiently shown by his brief reference to time of flowering considered as a character (p. 65). The hybrids, he says, flower at a time _almost exactly intermediate_ between the flowering times of the parents, and he remarks that the development of the hybrids in this case probably happens in the same way as it does in the case of the other characters[78]. [78] “_Ueber die Blüthezeit der Hybriden sind die Versuche noch nicht abgeschlossen. So viel kann indessen schon angegeben werden, dass dieselbe fast genau in der Mitte zwischen jener der Samen- und Pollenpflanze steht, und die Entwicklung der Hybriden bezüglich dieses Merkmales wahrscheinlich in der nämlichen Weise erfolgt, wie es für die übrigen Merkmale der Fall ist._” Mendel, p. 23.