[PAULUS libro uicensimo octauo ad edictum. ] §12.1.6.prCertum est, cuius species uel quantitas, quae in obligatione uersatur, aut nomine suo aut ea demonstratione quae nominis uice fungitur qualis quantaque sit ostenditur.
[PAULUS, On the Edict, book 28] An object is certain when its species or quantity, which is involved in the obligation, is shown to be of what kind and of what amount it is, either by its own name or by that demonstration which performs the function of a name.
nam et Pedius libro primo de stipulationibus nihil referre ait, proprio nomine res appelletur an digito ostendatur an uocabulis quibusdam demonstretur: quatenus mutua uice fungantur, quae tantundem praestent.
For Pedius also says in the first book On Stipulations that it makes no difference whether a thing is called by its proper name, or pointed out with a finger, or described by certain words; insofar as those things which achieve the same effect perform a mutual function.