Bei einer verhältnissmässig kleinen Anzahl von Versuchspflanzen konnte dann das Resultat nur annähernd richtig sein und in einzelnen Fällen nicht unbedeutend abweichen.
With a relatively small number of experimental plants, the result could then be approximately right only and deviate not insignificantly in individual cases.
quantity = Anzahl See p. 3, s. 8.
could = konnte Again, indicative past tense, rather than subjunctive; see p. 39, s. 2. Mendel claims that Gärtner and Kölreuter did raise very few offspring from their crosses, which is generally true. In most of their experiments, they actually observed that fertility was lowered to varying degrees.