present in proportion to it, it is obvious that those portions of
the organism would have most "light" which were most active
mentally--i.e., the brain and those portions of the nervous system
controlling the hands, face, and upper portions of the body--while those
portions which had become entirely automatic and unconscious in their
activity would have least light--being physiological to the point almost
of being mechanical. If this "light" corresponded in any way to
visibility, therefore, it would only be natural to suppose that the face
and upper portions of the phantasmal figure should be more or less
distinctly visible, to one at all sensitive to such impressions, while
the lower portions of the figure would fade into practical
invisibility,--owing to lack of "light." This explanation would
certainly be in accord with the facts, as we know them, regarding
phantasmal figures.

12. We are still far from the answer to our question, however: How does
spirit act upon matter, and in what way does the spirit manipulate the
nervous mechanism of the medium, during the process of communication?
Let us now consider this question further.

Andrew Jackson Davis, in his _Great Harmonia_, vol. i. pp. 55-65,
discussed this problem, and stated that "spirit acts upon the bodily
organism anatomically, physiologically, mechanically, chemically,
electrically, magnetically, and spiritually." The trouble with such a
statement is that it explains nothing (even as elaborated by him), and
that it is far easier to believe, e.g., that one part of the body acts
chemically and mechanically, etc., upon another part than to suppose
that "spirit" has anything to do with the affair whatever. To postulate
its activity would be merely to multiply causes without necessity.

Just here, it might be interesting to inquire what the modern conception
is as to the relation of mind and brain--of soul and body; and
particularly the question of the "seat" of the soul--that central point
which was, until late years, always considered necessary as a fulcrum or
point of contact upon which the soul might act.

The older psychologists and philosophers always took such a "seat" for
granted--Descartes, as we know, imagining that the pineal gland occupied
that important function. But as the science of psychology progressed,
this notion was more and more given up, until the prevailing opinion of
late years seems to be that the _whole_ of the cortex is equally the