Das Gesetz der Combinirung der differirenden Merkmale, nach welchem die Entwicklung der Hybriden erfolgt, findet demnach seine Begründung und Erklärung in dem erwiesenen Satze, dass die Hybriden Keim- und Pollenzellen erzeugen, welche in gleicher Anzahl allen constanten Formen entsprechen, die aus der Combinirung der durch Befruchtung vereinigte[n] Merkmale hervorgehen.
The law of combination of differing traits, according to which the development of hybrids occurs, thus finds its rationale and explanation in the proven proposition that the hybrids produce germ- and pollen cells that correspond in equal quantities to all the constant forms that emerge from the combination of the traits that were united by fertilisation.
law of combination of differing traits = Gesetz der Combinirung der differirenden Merkmale Mendel probably refers to his statement on p. 22, s. 7 that “the descendants of hybrids, in which several essentially different traits are united, represent the members of a combination series”, since this is the only law-like statement that directly makes reference to the “combination” of “differing” traits . In a statement opening the next section of his paper, Mendel seems to refer back to this law as “the developmental law found for Pisum” (see p. 32, s. 4). It is striking that Mendel distinguishes strictly here between “laws” that formulate empirical regularities, and an underlying reproductive process that explains these regularities. In that sense, Mendel does not formulate any “genetic laws” at all (see p. 18, s. 7, for further discussion). As a statement in the last section of his paper indicates, he rather seems to believe that empirical regularities or “laws” observed in organisms are contingent on “the unity in the developmental plan of organic life” (see p. 42, s. 10; cf. p. 3, s. 6 and p. 4, s. 1. also on Mendel’s more general understanding of laws and evolution). There are instances in Mendel’s paper, however, where he also delivers an “explanation” of observed trait distributions invoking the “law of combination” only; see p. 36, s. 1.
rationale and explanation = Begründung und Erklärung This was underlined by Mendel in his manuscript, but this emphasis was apparently not reproduced by the printer.
quantities = Anzahl See p. 3, s. 8.
constant forms = constanten Formen See p. 15, s. 7. In the manuscript, konstanten was inserted later in Mendel’s hand.
united = vereinigte[n] Bateson has “brought together”; see p. 41, s. 6. The original printed text has vereinigter which was corrected manually by Mendel in the offprint.