Let us now consider pluricellular organisms and consider them particularly from the standpoint of organic evolution. The pluricellular organism is nothing more nor less than a later development, a confederated a.s.sociation of unicellular organisms. Mark the development of such an a.s.sociation.

[Sidenote: Evolutionary Differentiation]

Originally each separate cell performed all the functions of a separate life. The bonds that united it to its fellows were of the most transient character. Gradually the necessities of environment led to a more and more permanent grouping, until at last the bonds of union became indissoluble.

Meanwhile, the great laws of "adaptation" and "heredity," the basic principles of evolution, have been steadily at work, and slowly there has come about a differentiation of cell function, an apportionment among the different cells of the different kinds of labor.

[Sidenote: Plurality of the Individual]

As the result of such differentiation, the pluricellular organism, as it comes ultimately to be evolved, is composed of many different kinds of cells. Each has its special function. Each has its field of labor. Each lives its own individual life. Each reproduces its own kind. Yet all are bound together as elements of the same "cell society" or organized "cell state."

Among pluricellular organisms man is of course supreme. He is the one form of animal life that is most highly differentiated.

[Sidenote: Combined Consciousness of the Millions]

Knowing what you now know of microscopic anatomy, you cannot hold to the simple idea that the human body is a single life-unit. This is the nave belief that is everywhere current among men today. Inquire among your own friends and acquaintances and you will find that not one in a thousand realizes that he is, to put it jocularly, singularly plural, that he is in fact an a.s.semblage of individuals.

[Ill.u.s.tration: MICROSCOPIC STUDIES IN HUMAN ANATOMY, PRIVATE LABORATORY, SOCIETY OF APPLIED PSYCHOLOGY]

Not only is the living human body as a whole alive, but "every part of it as large as a pin-point is alive, with a separate and independent life all its own; every part of the brain, lungs, heart, muscles, fat and skin." No man ever has or ever can count the number of these parts or cells, some of which are so minute that it would take thousands in a row to reach an inch.

"Feeling" or "consciousness" is the sum total of the feelings and consciousness of millions of cells, just as an orchestral harmony is a composite of the sounds of all the individual instruments.

[Sidenote: Evolution of the Human Organism]

In the ancient dawn of evolution, all the cells of the human body were of the same kind. But Nature is everywhere working out problems of economy and efficiency. And, to meet the necessities of environment, there has gradually come about a parceling out among the different cells of the various tasks that all had been previously called upon to perform for the support of the human inst.i.tution.

This differentiation in kinds of work has gradually brought about corresponding and appropriate changes of structure in the cells themselves, whereby each has become better fitted to perform its part in the sustenance and growth of the body.

[Sidenote: The Crowd-Man]

When you come to think that these processes of adaptation and heredity in the human body have been going on for _countless millions of years_, you can readily understand how it is that the human body of today is made up of more than thirty different kinds of cells, each having its special function.

[Sidenote: Functions of Different Human Cells]

We have muscle cells, with long, thin bodies like pea-pods, who devote their lives to the business of contraction; thin, hair-like connective tissue cells, whose office is to form a tough tissue for binding the parts of the body together; bone cells, a trades-union of masons, whose life work it is to select and a.s.similate salts of lime for the upkeep of the joints and framework; hair, skin, and nail cells, in various shapes and sizes, all devoting themselves to the protection and ornamentation of the body; gland cells, who give their lives, a force of trained chemists, to the abstraction from the blood of those substances that are needed for digestion; blood cells, crowding their way through the arteries, some making regular deliveries of provisions to the other tenants, some soldierly fellows patrolling their beats to repel invading disease germs, some serving as humble scavengers; liver cells engaged in the menial service of living off the waste of other organs and at the same time converting it into such fluids as are required for digestion; windpipe and lung cells, whose heads are covered with stiff hairs, which the cell throughout its life waves incessantly to and fro; and, lastly, and most important and of greatest interest to us, brain and nerve cells, the brain cells const.i.tuting altogether the organ of objective intelligence, the instrument through which we are conscious of the external world, and the nerve cells serving as a living telegraph to relay information, from one part of the body to another, with the "swiftness of thought."

Says one writer, referring to the cells of the inner or true skin: "As we look at them arranged there like a row of bricks, let us remember two things: first, that this row is actually in our skin at this moment; and, secondly, that each cell is a living being--it is born, grows, lives, breathes, eats, works, decays and dies. A gay time of it these youngsters have on the very banks of a stream that is bringing down to them every minute stores of fresh air in the round, red corpuscles of the blood, and a constant stream of suitable food in the serum. But it is not all pleasure, for every one of them is hard at work."

[Sidenote: Cell Life After Death]

And again, speaking of the cells that line the air-tubes, he says: "The whole interior, then, of the air-tubes resembles nothing so much as a field of corn swayed by the wind to and fro, the princ.i.p.al sweep, however, being always upwards towards the throat. All particles of dust and dirt inhaled drop on this waving forest of hairs, and are gently pa.s.sed up and from one to another out of the lungs. When we remember that these hairs commenced waving at our birth, and have never for one second ceased since, and will continue to wave a short time after our death, we are once more filled with wonder at the marvels that surround us on every side."

[Sidenote: Experiments of Dr. Alexis Carrel]

Remarkable confirmatory evidence of the fact that every organ of the body is composed of individual cell intelligences, endowed with an instinctive knowledge of how to perform their special functions, is found in the experiments of Dr. Alexis Carrel, the recipient of the n.o.bel prize for science for 1912.

_Dr. Carrel has taken hearts, stomachs and kidneys out of living animals, and by artificial nourishment has succeeded in keeping them steadily at work digesting foods, and so on, in his laboratory, for months after the death of the bodies from which they were originally taken._

[Sidenote: Man-Federation of Intelligences]

We see, then, that every human body is an exceedingly complex a.s.sociation of units. It is a marvelously correlated and organized community of countless microscopic organisms. It is a sort of _cell republic_, as to which we may truthfully paraphrase: Life and Union, One and Inseparable.

Every human body is thus made up of countless cellular intelligences, each of which instinctively utilizes ways and means for the performance of its special functions and the reproduction of its kind. These cell intelligences carry on, without the knowledge or volition of our central consciousness--that is to say, _subconsciously_--the vital operations of the body.

[Sidenote: Creative Power of the Cell]

Under normal conditions, conditions of health, each cell does its work without regard to the operations of its neighbors. But in the event of accident or disease, it is called upon to repair the organism. And in this it shows an energy and intelligence that "savor of creative power."

With what promptness and vigor the cells apply themselves to heal a cut or mend a broken bone! In such cases all that the physician can do is to establish outward conditions that will favor the co-operative labors of these tiny intelligences.

_The conclusion to be drawn from all this is obvious. For, if every individual and ultimate part of the body is a mind organism, it is very apparent that the body as a whole is peculiarly adapted to control and direction by mental influences.

[Sidenote: Laying the Foundation for Practical Doing]

Do not lose sight of the fact that in proving such control we are laying the foundation for a scientific method of achieving practical success in life, since all human achievement comes about through some form of bodily activity._

We a.s.sume now your complete acceptance of the following propositions, based as they are upon facts long since discovered and enunciated in standard scientific works:

_a_. The whole body is composed of cells, each of which is an intelligent ent.i.ty endowed with mental powers commensurate with its needs.

[Sidenote: Three New Propositions]

_b._ The fact that every cell in the body is a _mind_ cell shows that the body, by the very nature of its component parts, is peculiarly susceptible to mental influence and control.

To these propositions we now append the following:

_c._ A further examination of the body reveals a central mental organism, the brain, composed of highly differentiated cells whose intelligence, as in the case of other cells, is commensurate with their functions.

_d._ It reveals also a physical mechanism, the nervous system, peculiarly adapted to the communication of intelligence between the central governing intelligence and the subordinate cells.

[Sidenote: An Instrument for Mental Dominance]

_e._ The existence of this mind organism and this mechanism of intercommunication is additional evidence of the control and direction of bodily activities by _mental energy_.

The facts to follow will not only demonstrate the truth of these propositions, but will disclose the existence within every one of us of a store of mental energies and activities of which we are entirely unconscious.

The brain const.i.tutes the organ of central governing intelligence, and the nerves are the physical means employed in bodily intercommunication.

Brain and nerves are in other words the physical mechanism employed by the mind to dominate the body.

[Sidenote: Gateways of Experience]

Single nerve fibers are fine, thread-like cells. They are so small as to be invisible to the naked eye. Some of them are so minute that it would take twenty thousand of them laid side by side to measure an inch. Every nerve fiber in the human body forms one of a series of connecting links between some central nerve cell in the brain or spinal cord on the one hand and some bodily tissue on the other.

All nerves originating in the brain may be divided into two cla.s.ses according as they carry currents to the brain or from it. Those carrying currents to the brain are called _sensory_ nerves, or nerves of sensation; those carrying currents from the brain are called _motor_ nerves, or nerves of motion.

[Sidenote: Couriers of Action]

Among the sensory nerves are the nerves of consciousness; that is, the nerves whereby we receive sense impressions from the external world.