A French tradition asks: If the handle of a certain knife is replaced whenever it is worn out, and its blade is replaced whenever it becomes worthless, does the knife itself become immortal?

In his 1872 short story “Dr. Ox’s Experiment,” Jules Verne mentions a curious tradition of marriage within the Van Tricasse family:

From 1340 it had invariably happened that a Van Tricasse, when left a widower, had remarried a Van Tricasse younger than himself; who, becoming in turn a widow, had married again a Van Tricasse younger than herself; and so on, without a break in the continuity, from generation to generation. Each died in his or her turn with mechanical regularity. Thus the worthy Madame Brigitte Van Tricasse had now her second husband; and, unless she violated her every duty, would precede her spouse — he being ten years younger than herself — to the other world, to make room for a new Madame Van Tricasse.

Is this a series of distinct marriages — or one immortal union?

See The Ship of Theseus.