Art. 58 al. 1 O.G.; admissibility of federal appeal against a cantonal ruling on jurisdiction in divorce proceedings. Only decisions of the last cantonal instance that constitute a final judgment on the merits, i.e. that definitively dispose of the substantive claim, are appealable. Procedural preliminary rulings, in particular decisions denying jurisdiction, are excluded from appeal even if they terminate the proceedings in the instance concerned. The fact that competence is examined ex officio does not alter the nature of the ruling as a non-final procedural decision (consid. 1).