ABSTRACT
Among the extraordinary phenomena, which have still to be taken on trust, is one which was familiar to the mesmerists of the past and vouched for by men of learning and good standing, namely clairvoyance, that is, the seeing of objects that are invisible to the ordinary sight. Anyone examining the voluminous literature on the subject must admit that at all events some of the experimenters took every possible precaution to prevent self-deception or fraud.
