For our present discussion, let us regard man as being a living, thinking entity - a functionating organism that nourishes himself, breathes, moves, grows, and reproduces, adapting himself to his environment, both acting and reacting under the influence of innumerable internal and external stimuli.

His body, with its structures, organs, and parts, is composed of millions on millions of cells, each one of which, however much it may differ in structure and function from those belonging to other organs and tissues than its own, is a lineal descendant from a single primordial cell. Just how the mind of man is related to the brain and nervous system is as yet far from being clear, but we do know that as the brain is, so is the mind, and that a healthy, well-developed mind corresponds to a healthy, well-trained, well-developed, and well-nourished nervous system.

In the use of such expressions as "soul" and "spirit" in this discussion, it is with the same meaning as the word "mind," and to suggest that the individual has emotion, feeling, and will as well as intellect.

Emotion and will are frequently regarded as spiritual, intellect as mental, and sensation as physical, but they are all qualities of the same individual body, mind, soul, or spirit. So, in the sense that I use the term "mind," let it be held to embrace or include the whole of man's psychic or mental activities, conscious and subconscious, voluntary and involuntary.

Let us think of the human mind as being manifested by or through the sum total of the functions of every cell in the body, expressed in thought, feeling, volition, action, motion, perception, conception, memory, etc.

When I say action and motion, think not only of objective, conscious, external action and motion - such as feeling, seeing, hearing, reading, talking, walking, or other conscious sensations and acts - but also of subjective, unconscious, internal action and motion, including even the action of the lowest cell in the body in its ability to take in new matter, fix it, change it, and throw it off.

In one sense, each cell seems to have a mind of its own, for it goes on performing its special functions, be it brain cell, gland, muscle, bone, or skin cell. Yet no one of these microscopic organisms is capable of independent existence. Each has its duty to perform, but each in turn is dependent, at least in a very large degree, for its own existence upon the activity of other cells of the body, the functionating of which constitutes the complex mechanism of the animal physiology.