Conclusion

How they escape from their graves and return to them for certain hours
every day, without displacing the clay or leaving any trace of
disturbance in the state of the coffin or the cerements, has always been
admitted to be utterly inexplicable. The amphibious existence of the
vampire is sustained by daily renewed slumber in the grave. Its horrible
lust for living blood supplies the vigor of its waking existence. The
vampire is prone to be fascinated with an engrossing vehemence,
resembling the passion of love, by particular persons. In pursuit of
these it will exercise inexhaustible patience and stratagem, for access
to a particular object may be obstructed in a hundred ways. It will
never desist until it has satiated its passion, and drained the very
life of its coveted victim. But it will, in these cases, husband and
protract its murderous enjoyment with the refinement of an epicure, and
heighten it by the gradual approaches of an artful courtship. In these
cases it seems to yearn for something like sympathy and consent. In
ordinary ones it goes direct to its object, overpowers with violence,
and strangles and exhausts often at a single feast.

The vampire is, apparently, subject, in certain situations, to special
conditions. In the particular instance of which I have given you a
relation, Mircalla seemed to be limited to a name which, if not her real
one, should at least reproduce, without the omission or addition of a
single letter, those, as we say, anagrammatically, which compose it.

Carmilla did this; so did Millarca.