Differentiarum libri
Ex libro III
Dig. 7,4,21Modestinus libro tertio differentiarum. Si usus fructus civitati legetur et aratrum in ea inducatur, civitas esse desinit, ut passa est Carthago, ideoque quasi morte desinit habere usum fructum.
Modestinus, Differences, Book III. Where an usufruct is bequeathed to a city, and the site of it is afterwards turned into a plowed field, it ceases to be a city, as was the fate of Carthage; therefore it ceases to have the usufruct, just as in case of death.