The successful reading of the history of the specimens submitted to the percipients is therefore easily accounted for where the professor had conscious knowledge of the contents of the packages. It remains only to explain the reason of success when he sought to eliminate that element by submitting a large number of similar packages, not consciously knowing one from the other. This also is easy to understand when the extraordinary acumen of the subjective mind is considered. It is a common hypnotic experiment to draw a blank card from a package, hand it to a subject, and suggest that it contains a picture of some person. The card is then marked on the back and shuffled with fifty or more others. A good subject will, in nine cases out of ten, indicate the marked card as the one containing the suggested picture, and that without the possibility of seeing the mark on the other side. It is obviously a much easier feat to remember the differences in packages than in blank cards. Of the former, no two could possibly be alike. Of the latter, no two would ordinarily be sufficiently unlike to enable one to determine the difference by the unaided senses. But to the subjective mind the feat of remembering each package and its contents would be very easy, compared with thousands of recorded instances to be found in the literature of psychic phenomena. It will be observed that we have refrained from invoking the aid of clairvoyance to account for the phenomena of psychometry. It would be a much simpler solution of the problem to assume that the power of independent clairvoyance exists, and that the percipients simply saw the contents of the packages. But inasmuch as the known facts of telepathy afford a perfect solution, we are not logically justified in entering a domain which is in the slightest degree overshadowed by doubt. By this remark it is not meant to imply that there is any doubt of the existence of a power which is generally known as clairvoyance, but that its limitations are as yet undecided. That is to say, the boundary line between clairvoyance and telepathy is not at present clearly drawn. The field of clairvoyance is constantly narrowing its boundaries. Thus, a few years ago every perception of a fact not cognizable by the senses was attributed either to clairvoyance or to spirits. Sceptics on the latter subject were wont to explain certain phenomena by attributing them to the former. The phenomena which could not thus be explained were relegated to the domain of fraud and legerdemain. When the phenomena of telepathy became better understood, the field of clairvoyance was greatly narrowed, as it was found that most of the phenomena before explained by clairvoyance were really due to telepathic communion. But the powers and limitations of telepathy are not yet clearly marked; and it is found that every step in advance in the knowledge of its principles by just so much narrows the field of clairvoyance.