mere sitting idly round a table, and calling the process a seance,
produces evil effects.

As to the idea of purposely evoking the dead, it is at least as
impious, as absurd, as odious to taste and sentiment, as it is
insane in the eyes of reason. This protest the writer feels obliged
to make, for while he regards the traditional, historical and
anthropological curiosities here collected as matters of some
interest, in various aspects, he has nothing but abhorrence and
contempt for modern efforts to converse with the manes, and for all
the profane impostures of 'spiritualism'.

On the question of the real existence of the reported phenomena
hereafter chronicled, and on the question of the portee of the
facts, if genuine, the writer has been unable to reach any
conclusion, negative or affirmative. Even the testimony of his
senses, if they ever bore witness to any of the speciosa miracula,
would fail to convince him on the affirmative side. There seems to
be no good reason why one observer should set so much store by his
own impressions of sense, while he regards those of all other
witnesses as fallible. On the other hand, the writer feels unable
to set wholly aside the concurrent testimony of the most diverse
people, in times, lands and conditions of opinion the most various.
The reported phenomena fall into regular groups, like the symptoms
of a disease. Is it a disease of observation? If so, the topic is
one of undeniable psychological interest. To urge this truth, to
produce such examples as his reading affords, is the purpose of the
author.

The topic has an historical aspect. In what sorts of periods, in