graphs, relating to nervous impressions, their
registry, and the consequences, that spring from them, I have given an
abstract of views presented in my work on "Human Physiology," published
in 1856, and may, therefore, refer the reader to the chapter on "Inverse
Vision, or Cerebral Sight;" to Chapter XIV., Book I.; and to Chapter
VIII., Book II.; of that work, for other particulars.

The only path to scientific human psychology is through comparative
psychology. It is a long and wearisome path, but it leads to truth.

Is there, then, a vast spiritual existence pervading the universe, even
as there is a vast existence of matter pervading it--a spirit which,
as a great German author tells us, "sleeps in the stone, dreams in the
animal, awakes in man?" Does the soul arise from the one as the body
arises from the other? Do they in like manner return, each to the source
from which it has come? If so, we can interpret human existence, and our
ideas may still be in unison with scientific truth, and in accord with
our conception of the stability, the unchangeability of the universe.

To this spiritual existence the Saracens, following Eastern nations,
gave the designation "the Active Intellect." They believed that the soul
of man emanated from it, as a rain-drop comes from the sea, and, after a
season, returns. So arose among them the imposing doctrines of emanation
and absorption. The active intellect is God.

In one of its forms, as we have seen, this idea was developed by Chakia
Mouni, in India, in a most masterly manner, and embodied in the vast
practical system of Buddhism; in another, it was with less power
presented among the Saracens by Averroes.

But, perhaps we ought rather to say that Europeans hold Averroes as
the author of this doctrine, because they saw him isolated from his
antecedents. But Mohammedans gave him little credit for originality.
He stood to them in the light of a commentator on Aristotle, and as
presenting the opinions of the Alexandrian and other philosophical
schools up to his time. The following excerpts from the "Historical
Essay on Averroism," by M. Renan, will show how closely the Sarscenic
ideas approached those presented above:

This system supposes that, at the death of an individual, his
intelligent principle or soul no longer possesses a separate existence,
but returns to or is absorbed in the universal mind, the active
intelligence, the mundane soul, which is God; from whom, indeed