Eine berechnete Auswahl war daher bloss bei dem ersten Versuche möglich, bei dem zweiten mussten auf den blossen Zufall hin, einige Pflanzen ausgeschieden werden.
A calculated selection was therefore possible in the first experiment only; in the second some plants had to be set aside on the basis of pure chance.
The second comma is wrongly placed according to German rules of punctuation, and is missing in the manuscript.
calculated = berechnete Bateson has “definite”, Sherwood “intentional”. We have chosen a literal translation; the gerund form berechnend of the verb berechnen connotes cunning. The difference Mendel highlights here consists in the fact that the first experiment will produce plants that exhibit recessive traits in F2. This allows, as Mendel demonstrates in the following, to complete transformation more quickly, since in transformation experiments one selects the forms “closest” to the species aimed at, i.e species B in experiment 1, for further crossing (see p. 43, s. 3). In the second experiment, none of the plants in F2 appear “closer” to species A, since they all exhibit the same dominant traits of A, masking recessive factors, that may then reappear in F3 due to segregation. Since for Mendel it is not only external traits that define a species, but also their constancy (see p. 6, s. 14), segregation will mean that the trait in question has not been produced. While he does not say so here, he states it very clearly in his conclusion from the experiment; see p. 46, s. 3.
set aside = ausscheiden Literally, to “segregate” or “separate”. The term has a technical meaning, e.g. in chemistry, but context makes clear that Mendel is simply speaking of the random selection of a sample.