In the living cell there is an interplay of the energy of masses of molecules forming the granules, of single molecules in watery solution, of atoms which compose the molecules, and of electrons, the various groupings of which compose the atoms of the elements. The elements themselves are now recognised to be transmutable through simplification and rearrangement of their electronic structure, and to be evolved out of one primordial electronic unit, a unit of energy, unknowable in nature, out of the groupings and transmutations of which arise all manner of living and non-living forms, the apparently indestructible stable materials being no less in a state of flux and evolution than the most unstable. The complexity of the transmutations of energy and ultimate unknowableness and mystery of their cause are no less in the case of a drop of water or a particle of dirt than in that of a living cell. The scientific conception of the universe, the very opposite of materialism, approaches pantheism.
The living substance of a uni-cellular organism, similarly the congery of cells forming the body of man, has evolved the power of sensing and of moving towards, or away from life-giving or destroying sources of energy. Special sense-organs, receptive of one or other form of energy have been evolved through the æons of the struggle for existence, together with nervous and muscular systems, to enable him to preserve his life in the midst of the shocks and thrills of his environment. There are also evolved inner senses, and a sympathetic nervous system which knits all parts of the body in harmonious action; the community of action also being brought about by the circulating fluids of the body, the blood and the lymph, to which each living cell gives and from which each cell takes. For communion with the environment, eyes for visual, and sense organs in the skin for thermal radiant energy have been perfected, ears for sound waves travelling through air, taste organs for substances in solution, smell organs for particles of substances floating in the atmosphere, touch organs for sensing movements of masses.
The receptive cells of the special sense organs are composed of watery, granular, living substance and elaborate mechanisms have been evolved for converting one or other form of energy into such a form that it can be received by the living substance, e.g. the intricate structure of the eye with its focussing lenses, retinal cells laden with pigment sensitive to light, the ear with its drum membrane vibrating in unison with sound waves in the air, its chain of transmitting osicles, and complicated receiving organ placed in the spiral turns of the cochlea. Be it noted, the receptive cells of the sense organs are immersed in fluid, and each sense organ is specifically sensitive, i.e. only to that form of energy which it has been evolved to receive through countless ages of evolution.
The nervous system is composed of myriads of nerve cells, and of nervous fibres, which are long and exceedingly slender processes of these cells formed of similar substance, each shielded and insulated by a double coat. The nerve cells and the nerves are arranged in an ordered plan which has been unravelled by ingenious methods. They connect all parts of the body one with another. Think of the whole telephone system of Britain linked up together with millions of receivers, thousands of local exchanges, hundreds of central exchanges, etc., the nervous system with its sense organs, sensory nerves, lower and higher nerve centres and motor nerves, is infinitely more intricate than that. The whole forms an interlacing feltwork formed of watery nerve cells and processes, and not only receives sensory stimuli and transmits them as motor impulses, but is more or less permanently modified by each sensory thrill which enters it, memorising each, more or less, for longer or shorter time according to its character or intensity. Thus the response of the nervous system to sensory excitation changes with education, habits form and character develops from birth to manhood, to decay again from manhood to old age, ceaselessly changing, but becoming graved on a certain plan. The making thereof depends on inborn qualities of the living substance—the conjugate product of the male and female parents, this moulded by environmental conditions, both in utero and after birth, by food, and the ceaseless instreaming of sensations. Depending on the nutrition of the cortex of the great brain, abrogated by narcotics, absent in sleep, consciousness of our being flickers from moment to moment, the product of the instreaming of sensations from the outer world and from our own body, and of memories of past sensations, aroused, by some present sensation. Conscious judgement arises from the balancing of present sensations with memorised sensations and leads to purposeful actions.
Beneath the conscious world an infinite host of functions are carried out unconsciously, functions depending on the nervous connection of one part with another, just as the common people carry out a host of actions through the telephone system without the cognisance of the government which is seated at the highest central exchange.
To find food, satisfy the sexual instinct, escape enemies, gain shelter from excessive physical changes of environment, the special senses and nervous system have then been evolved and perfected in the intricacy of their mechanism through vast æons of evolution. There is evidence that man has for some million years trod the earth; but the senses of sight, hearing, smell, taste, touch were evolved in the vast procession of lower animals which preceded him for those millions of years which reach back and ever back to the first generation of life.
The realisation of these facts saves the physiologist from being deceived, either by fraudulent tricks or those natural chances of human occurrence which occasion the belief of the credulous in telepathy. He recognises that the human nervous system is built on a common plan, and that it is to be expected that the sensory stimuli received from a given environmental condition will often arouse the same train of thought in two or more people, standing together, especially in those who habitually associate. Such coincidences of thought, which astonish the ignorant, are due to natural law. Human experience shows that judgements of fundamental importance which would, if transmittable to another at a distance by telepathy, win a fortune, save a defeat, etc., are never so transmitted. The Stock Exchange and the army in the field must have their telephone and telegraph systems and messengers. No more concentrated will to send information, which might bring succour, say from the artillery, could be given than by men in peril of their lives in the trenches, when the enemy came swarming over the top, but we know that with the wires cut and the human messengers killed no succour came. Neither does it come to the liner which, in full proud course with its freight of thousands of souls strikes an iceberg, unless the wireless mechanism be installed and operated so that the S.O.S. signal is despatched. Otherwise it sinks without trace, as the Germans advised their 'U' boats to let their victim merchant ships sink.
The phenomena of wireless telegraphy and of radio-active elements have led people to think that some direct means of communication of energy from one brain to another may be possible, that is without intervention of the special senses. There is not the least evidence in favour of this view; the evolution of the senses is wholly against it. It is true that all vital activity is accompanied by electrical change—by a flow of electrons—in the living matter, the nervous impulse itself may be so transmitted. Such electrical change by a special evolution of structure is magnified in the electric organ of certain fishes and used by them as a weapon of offence. It is then sensed just as an electric shock from a battery is sensed, and the intensity of the shock lessens inversely as the square of the distance. There is no evidence that the minute electrical changes accompanying nervous action in man are transmittable to a distance through space; the nerves are evolved to confine and convey these as nerve impulses to suitable receivers within their body whereby function is co-ordinated.
A radio-active element enters into the composition of the living matter, e.g. potassium. A nutritive fluid can be prepared from a watery solution of sodium calcium and potassium salts capable of keeping the excised heart of the frog in action. The place of potassium in this fluid can be taken by the energy radiated from radio-active material placed suitably near the weak solution of the other two salts which contains the heart. Too strong a radiation kills the heart. Wonderful as this new discovery is it is comparable with the well-known fact that the radiant energy of the sun—either heat rays or the cold ultraviolet rays of intense chemical action—while beneficent, when properly graded, kill the living substance which is over-exposed to them. Hence the evolution of the green colour of plants and the pigment in the skin of animals, which acts as screens.
It has recently been shown that trees pick up the long waves used in wireless telegraphy, and can be used as receivers, but there is no evidence that animals are sensitive to these waves. No one knew either of their existence or of that of magnetic storms until instruments were invented suitably tuned to pick up the waves of energy and demonstrate them to one or other of man's special senses—sight, hearing or touch.