In der That lässt sich auf theoretischem Wege zeigen, dass diese Annahme vollständig ausreichen würde, um die Entwicklung der Hybri- den in den einzelnen Generationen zu erklären, wenn man zugleich voraussetzen dürfte, dass die verschiedenen Arten von Keim- und Pollenzellen an der Hybride durchschnittlich in gleicher Anzahl gebildet werden.
It is indeed possible to demonstrate along theoretical lines that this assumption would suffice to explain the development of hybrids in each individual generation, if at the same time one were allowed to presuppose that the different species of germ- and pollen cells are formed in equal quantity on average on the hybrid.
along theoretical lines = auf theoretischem Wege This is what Mendel indeed does in Section 7, where he generalises his empirical results from monohybrid crosses under the assumption that each plant produces four descendants, which in the case of hybrids always results in a ratio of 1 : 2 : 1 of hybrid and respective pure forms (see p. 17, s. 9). It is significant that Mendel thought it was necessary to test the assumption experimentally, as stated in the next sentence, rather than simply relying on the power of theoretical deduction.
quantity = Anzahl See p. 3, s. 8.
on the hybrid = an der Hybridpflanze See p. 10, s. 10.