ransforms every drop of blood in our bodies into the lists in which
phagocyte and microbe wage the mortal strife on which our health
depends. Every white corpuscle that swims in our veins is now declared
to be the armed Knight of Life for ever on the look-out for the microbe
Fiend of Death. Day and night, sleeping and waking, the white knights of
life are constantly on the alert, for on their vigilance hangs our
existence. Sometimes, however, the invading microbes come in, not in
companies but in platoons, innumerable as Xerxes' Persians, and then
"e'en Roderick's best are backward borne," and we die. For our life is
the prize of the combat in these novel lists which science has revealed
to our view through the microscope, and health is but the token of the
triumphant victory of the phagocyte over the microbe.

But far more enthralling is the suggestion which psychical science has
made as to the existence of a combat not less grave in the very inmost
centre of our own mental or spiritual existence. The strife between the
infinitely minute bacilli that swarm in our blood has only the interest
which attaches to the conflict of inarticulate and apparently
unconscious animalculae. The strife to which researches into the nature
and constitution of our mental processes call attention concerns our
conscious selves. It suggests almost inconceivable possibilities as to
our own nature, and leaves us appalled on the brink of a new world of
being of which until recently most of us were unaware.

There are no papers of such absorbing interest in the whole of the
"Proceedings of the Society for Psychical Research" as those which deal
with the question of the Personality of Man. "I," what am I? What is our
Ego? Is this Conscious Personality which receives impressions through
the five senses, and through them alone, is it the only dweller in this
mortal tabernacle? May there not be other personalities, or at least one
other that is not conscious, when we are awake, and alert, and about,
but which comes into semi-consciousness when we sleep, and can be
developed into complete consciousness when the other personality is
thrown into a state of hypnotic trance? In other words, am I one
personality or two? Is my nature dual? As I have two hemispheres in my
brain, have I two minds or two souls?

The question will, no doubt, appear fantastic in its absurdity to those
who hear it asked for the first time; but those who are at all familiar
wi