A Retrospect and Forecast of Animal Electricity and Magnetism in Light of Recent Knowledge.
By Dr. Henry Fotherby
LIKE many other great discoveries of science, animal electricity was found out by a seemingly chance coincidence. It happened in the year 1786 that whilst Galvani, Professor of Physiology and Anatomy at the University of Bologna, was engaged in making experiments, his frictional electric machine being in use at the time, that his wife was preparing some frogs' legs for their dinner, when she noticed to her surprise that whenever sparks were emitted from the former the latter became convulsed, although apparently dead. She at once called her husband's attention to the extraordinary fact, and it was this circumstance that led Galvani to make a series of experimental researches regarding the phenomenon.
His first experiments were to try the effect of lightning and atmospheric electricity upon frogs. For this purpose he hung some freshly prepared frogs' legs by copper wires along the iron trellis-work which surrounded the roof of his house, and he observed that they became contracted whenever the wind blew them against the iron. His explanation of the fact was that animal tissues secreted electricity. This view was, however, strongly contested by his scientific contemporaries, especially Volta, Professor of Physiology at the University of Pavia, who scouted the idea of the presence of animal electricity altogether and explained the contraction as due to artificial electricity produced by the contact [98] of the two dissimilar metals, iron and copper, present in the experiment. The controversy continued until Galvani's death in 1798. However, before he died, Galvani proved the existence of animal electricity by his now famous experiment known as "contraction without metals." This consisted in making a muscle nerve preparation from a fresh and vigorous frog, and by causing the nerve of it to be dropped on another fresh muscle preparation, or even on its own muscle, he showed that it led to a contraction of the muscle on which it is dropped. The presence of electric currents in muscles has since been demonstrated by the galvanometer and electrometer by interposing between their wires and the muscle preparation a non-polarisable electrode.
In 1779, a few years previous to Galvani's experiments, Walsh and Ingelhaus made a series of important investigations regarding the electrical phenomena present in certain fishes, namely the torpedo fish and electric eel, which have the power of producing shocks in animals, similar to those produced by an electric current.
These fishes possess complicated electric organs developed out of muscular tissue which have the power of accumulating electric force in large quantities and communicating it to other animals. The electric organ in the case of Rays is found between the head and the pectoral fins. It consists of a series of vertical prisms divided by horizontal partitions into separate cells, each of which is filled with a translucent jelly-like substance. In the Pikes it is found that the electric organ is modified muscle, "in which a series as it were of hypertrophied end-plates correspond to the plates of a voltaic pile. In other fishes the electric organ is composed of modified skin glands." (Halliburton.)
"The phenomenon attending the exercise of this extraordinary faculty closely resembles muscular action. The time and strength of the discharge are entirely under the [99] control of the fish. The power is exhausted after some time and needs repose and nourishment to restate it. If the electric nerves are cut and divided from the brain the cerebral action is interrupted and no irritant to the body has any effect in exciting electric discharge, but if the cut ends be irritated the discharge takes place just as when muscle is excited under similar circumstances. Singularly enough the application of strychnine causes a succession of involuntary electric discharges. The strength of the discharge depends entirely upon the size, health and energy of the fish. The electric currents created in these fishes exercise all the other known properties of electricity, they render a needle magnetic, decompose chemical compounds, and emit the spark. To receive the shock the object must complete the galvanic circuit by communicating with the fish at two distinct points either directly or through the medium of some conducting body. If an insulated frog touches the fish by the end of the nerve only, no muscular contraction takes place on the discharge of the battery or electric organ, but contact at a second point immediately produces it." (The Royal Natural History.)
By this it will be seen that the living organism, as in the above examples, is able to manifest electrical phenomena to a remarkable degree; the organs which produce them are formed of modified muscular tissue; this action closely resembles muscular action, and is under the control of the nervous system.
When, however, we come to ask the question, what is this nervous energy which travels along the nerves to cause a muscle to contract or an electric organ to discharge itself, etc., science as yet can give no definite answer. Physiologists hold that though it bears definite relations to electricity it is not electricity itself, since the rate at which its impulse travels is too slow to be thus explained, but that it is a form of ether vibration there can belittle or no doubt.
"When a nerve is stimulated the change produced in it is called a nerve impulse; this change travels along the nerve and the propagation of some change is evident from the effects which follow, sensation, movement, secretion, but in the nerve itself very little change can be detected. There is no change in form; the most delicate thermo-piles have failed to detect any production of heat, and we are also ignorant of any chemical changes. The only alteration which can be detected as evidence of this molecular change in the nerve is the electrical one. Healthy nerve is iso-electric, but during the passage of a nerve-impulse along it there is a very rapid diphasic variation, which travels at the same rate as the nerve impulse. This is similar to the diphasic change in muscle and can be detected in the same way. A nervous impulse is not electricity, compared with that of electricity its rate of propagation is extremely slow." (Halliburton.)
It may be noted here that the diphasic variation in a muscle is an electrical change that takes place during the twitch of a muscle. When a muscle contracts it becomes first more negative than before and then rapidly returns to its previously positive condition. This change indicates a molecular disturbance of the tissue, and is indicated by the movement of the galvanometer needle. When the muscle is at rest and absolutely uninjured it is, as in the case of nerve, iso-electric.
Whatever nervous energy is, it seems certain that it is the same in all nerves, whether in the optic nerve, a motor nerve, or one of ordinary sensation, as experiment has demonstrated that if a motor nerve is divided and the distal end united by suture to the proximal end of a divided sensory nerve, the latter will, as soon as union is completed, conduct motor impulses to the muscle, and vice versa. Everything therefore depends on the receiver or transmitter, in other words on the end-organs of the nerve which receive the impression, [101] on the one hand, whether it be a motor plate, a touch corpuscle, a rod of Corti, or Retinal cone, and on hand on the nerve cells in the cortex which receive, interpret or transmit sensations. The same stimulus when received by different end-organs will produce a different mental impression. Thus if you stimulate a muscle with an electric current you get motion; or the skin, the sense of touch; if applied to the ear, a sound; to the tongue, taste; or to the eye, a flash of light.
This nerve force was in early days believed to be analogous to magnetism, and people were credited by the old magnetisers with the possession of an aura or atmosphere which emanated from their bodies, and which, like magnetism, possessed polarity, and had the power of attraction and repulsion, and was capable of acting even over space. Hence the force was named by them — Animal Magnetism. This doctrine, however, was more or less confined to them, and obtained little credence amongst scientific men generally, although there were a few honest men of scientific eminence who held these views.
In 1820 Oersted discovered electro-magnetism. He found that when a galvanic current was passed along a wire near a magnetic needle, the needle was deflected one way or the other in accordance with the direction of the current. The astatic needle and galvanometer owe their invention to this discovery and later on the evolution of the dynamo, with the production of electro-motive force and electric light, was a further result.
In 1845, twenty-five years after Oersted's great discovery, Reichenbach made a series of experiments as to the influence of magnets, etc., on "sensitives," that is, people whose powers of perception are exalted above the normal standard by virtue of a highly strung and sensitive nervous system, or those in an abnormal state of consciousness through hypnosis, and the results he obtained, although [102] treated with indifference, and even contempt, by his scientific contemporaries, are so striking in the light of recent research and knowledge that I feel tempted to refer to them briefly in connection with my subject. Reichenbach found that when strong magnets were presented to these subjects they saw flame-like appearances proceeding from the poles and sides of the magnets, the same phenomenon was observed in the case of crystals, and, moreover, they were alleged to see "fiery bundles of light flow from the finger-tips of healthy men," in the same way as from the poles of magnets and crystals. He found also that the force present in magnets, crystals, and human beings could be transferred to other bodies, for instance, water, and could be transmitted even along a wire, so as to be recognised in each case by the sensitive. To this force he gave the name Od or Odyle, and he concluded that the human manifestation of it, namely animal magnetism, was but a new manifestation of the form of energy present in magnets and crystals, and, he believed, moreover, that although it is present in magnets it had an existence independent of them. "There appears," he says, "to be a force in the magnet which is different from magnetism, but which can be identified with the force in crystals," and again in another place he states: "One part of the collective force residing in the magnet; the crystalline force; and the force lying at the foundation of what is called animal magnetism — these three forces, in their essence, when regarded from a common point of view, coincide, and are identical."
He found, moreover, that his Odic force exhibited polarity, that it was capable of conduction to distances, but that its conduction was much slower than electricity; it was also present in solar radiations, and appeared to exist also in artificial light; bodies could be charged with it either by close proximity or contact, but to a less degree than the one that generates it, and the force, while [103] it lasted, in like manner exhibited polarity, but was quickly dissipated.
Discussing the luminous phenomena exhibited by Odic force, Reichenbach expresses himself as follows: "Odic flame is a material something, most probably a body rendered luminous, but not magnetism." Like electricity it is more evident in vacuo, and reduced atmospheric pressure. The light acts on a; photographic plate, and has so great a resemblance to the Aurora Borealis that Reichenbach considers the phenomena identical. "There remains," he says, "hardly any essential mark of distinction between magnetic light, and terrestrial polar light; unless we regard as such the difference of intensity and amount of light, in virtue of which the polar light is visible to every ordinary eye, the magnetic light only to the sensitive eye." [1]
The weak point in these observations of Reichenbach is that they so largely depend on the good faith of his sensitives, a class of people whose testimony is often unreliable, owing to the possibility of hypnotic suggestion causing them to see things subjectively which do not exist in fact, and also because no one in an ordinary state of consciousness has been able to verify the truth of these phenomena at first hand by the use of his senses. On the other hand, the argument for their plausibility gains considerable strength when it is seen how prophetic some of Reichenbach's experiments and conclusions were of what is now being reaffirmed by modern science. A volume of these researches was published by Reichenbach in 1845, and was translated into English by Dr. Gregory in 1850.
It is only in recent years that the interest in animal magnetism, or, in other words, nerve energy, has received a fresh impulse, and this is owing to the great and momentous [104] revolution which has taken place in physical science in regard to the new views on the nature of energy and matter during the last quarter of the nineteenth century. This is in great measure due to the researches of Sir William Crookes on the properties of radiant energy which were commenced by him in 1872, and also as a result of the brilliant mathematical deductions made by Clerk-Maxwell, who in the sixties gave the first hint of the existence of electro-magnetic waves, and who, working on the same lines, formulated in later years his great electro-magnetic theory of light. The experimental proof of the former was demonstrated in 1888 by his disciple Heinrich Hertz, through whose epoch-making experiments the means of communicating over space by means of electric waves has been discovered; and the latter is now generally accepted by men of science.
Following on Crookes' researches, we find Linard in 1894 adding important information to our knowledge of radiant energy, and two years later, in consequence of these observations, Professor Röntgen discovered that the cathode or X-rays given out by a Crookes' tube could, by the aid of photography produce skiagraphs of the bones of the human body and other substances. Shortly after, about the year 1898, Professor and Madame Curie, following up the work of the great French physicist, Henri Becquerel, on radio-activity, discovered radium and polonium respectively.
It would be out of place, besides taking up too much space, to even outline what has been done in the study of radio-activity, and the tremendous results which have arisen therefrom, or to mention the long list of great names which have been associated in this grand work. The great point which bears on our subject of nervous energy or animal magnetism. call it what you will, is that out of this mass of accumulated knowledge, a great scientific generalisation has arisen which stands hardly second to evolution itself in [105] importance, and this is the theory of a universal all-pervading ether which permeates all space, whether terrestrial or celestial, interstellar or intermolecular. This ether is regarded as an attenuated form of matter, which is neither solid, liquid, nor gaseous, but which Sir William Crookes regards as a fourth condition of it, the ultimate particles of which are called ions or electrons: and it is considered that all energy, such as light, heat. electricity, magnetism, etc., is due to the vibrations of these particles: — even the molecules of matter itself are now believed to be built up primarily of these etheric units.
It is hardly surprising, therefore, that speculations so vast and discoveries so almost magical as this Ether Theory on the one hand, and X-rays, wireless telegraphy, radium, etc., on the other, should have gone far to break down the old scientific conservatism and prejudice of former days, nor is it to be wondered at that when Professor Blondlot of Nancy announced in 1903 the discovery of certain new radiations, called by him N-rays, which were given out by certain substances, and when Professor Charpentier proved that these were given out in large quantities during nervous activity, that the results of their researches were received with respect and interest. As N-rays have now an established place in science, and since they have a special interest as regards the nature of nervous energy, I propose now to mention a few of their leading characteristics. These new radiations are ether vibrations of long wave-length and are near to electro-magnetic vibrations in point of frequency. They are given of by an incandescent gas flame, and can be separated from heat and light rays by filtration through aluminium-foil, which allows their passage through it whilst intercepting the rays of light and heat. Their presence can be demonstrated because they have the power of increasing the phosphorescence of a platino-cyanide of barium screen, and by causing a small, faintly luminous [106] bluish gas flame to be rendered whitish in colour and more luminous when these rays are focussed on it by means of a quartz lens.
N-rays are emitted by many different substances, for instance, wood, glass, wool and caoutchouc, when forcibly compressed or twisted. Tempered steel and hammered metals are permanent and spontaneous storers of these rays, but non-tempered steel is inactive. Solar radiations contain N-rays, and stones, quartz, Iceland spar, and fluor spar, when exposed to sunlight, become charged with them. These radiations are capable of reflection, refraction and polarisation.
The supreme interest of N-rays, however, is that they are given of largely by nerves and nerve centres, and Professor Charpentier demonstrated that their emission was greatly increased during functional activity, such as speaking or putting a muscle into action. Even the act of attention and mental effort was found to increase their activity, the evidence of which was shown by the increased phosphorescence of the platino-cyanide of barium screen.
Blondlot has observed that these rays will act on a photographic plate. He found that if a platino-cyanide of barium screen, which had been exposed to the influence of N-rays, and one that had not been so exposed, were photographed, the former produced the darker print of the two. This, taken with the facts that N-rays increase the luminosity of a feeble gas flame, and increase the phosphorescence of phosphorescent bodies such as platino-cyanide of barium, etc., suggests that these radiations must possess some intrinsic luminosity, although too faint to be seen by ordinary vision. Another interesting observation was made in 1905 by Professor Becquerel regarding these rays, namely, that animals put under the influence of chloroform cease to emit N-rays, but as soon as the influence of the anaesthetic passes of the emission of the radiations recurs. Moreover, [107] metals, crystals, and other substances which emit N-rays behave in like manner when so treated.
Quite recently Dr. Paul Joire, writing to The ANNALS OF PSYCHICAL SCIENCE, July, 1906, has shown that this nervous force (N-rays?) is capable of not only being detected, but even measured. He has proved, moreover, that it can be exteriorised in various other bodies. This he demonstrated by an instrument of his own invention — the Sthenometer. It consists essentially of a horizontal circular dial, marked out in 360 degrees, in the centre of which, balanced by a pivot on a glass support, is a light needle or pointer, most frequently made of straw. One arm of this pointer is much shorter than the other, and is weighted by a counterpoise to keep it in an horizontal position. The whole is covered with a glass shade. All possible sources of error having been eliminated, such as the action of heat, light, electricity, and sound, by special tests, it was found that, when the extended fingers of one's hand are brought near the side of the shade without touching it, at right angles to the pointer, after a few seconds, in the majority of cases, a decided movement of the pointer takes place, it being attracted towards the hand. This movement extends over fifteen, twenty, and sometimes up to forty and fifty degrees.
Dr. Joire observed also that not only do the extended fingers produce movements of the sthenometer needle, but also that certain substances which have been held in the hand produce movements, which, previous to being handled, caused no movement at all, thus proving the exteriorisation of this nerve energy.- The amount of movement varies with the nature of the substance, some materials produce no movement at all. In all cases it was found that the movement was not so powerful as with the hand which previously handled them. The objects which have been found incapable of storing this force are tin-foil, iron, cotton, and [108] those capable of storing it in different proportions are wood, water, linen, cardboard.
By this brief summary of Blondlot's, Charpentier's, and Joire's researches it will be seen how remarkably they are in accordance with many of Reichenbach's observations. Whether the N radiations of Blondlot and the nerve force of Joire coincide with Reichenbach's odic force or are only part of the radiations studied under that name is not yet ascertained. At first sight the alleged observation, if it is a fact, that Od presents luminosity would appear to contradict its being simply N radiations, but as before suggested it would appear that these radiations may be faintly luminous, but too slightly so for ordinary perception.
If, however, we go down the scale of animal life we shall find examples of luminous phenomena apparently of nervous origin. For instance amongst the beetles or Coleoptera, we find two sub-orders containing insects which have the power of emitting light — the Lampyridae, in which is found the glow-worm, and fire-fly of Southern Europe — and the Elaterida, to which belongs the fire-fly of Mexico and the West Indies. The glow-worm, Lampyris noctiluca, so well known in our hedge-rows, emits a most brilliant light at night. This property is chiefly confined to the wingless female although the winged male and pupa are also faintly luminous. The light appears to be under the nervous control of the insect, and to be influenced also by excitement. Joisel de Bellsome believes it to be caused by phosphoretted hydrogen gas stored in the cellular tissue and in direct communication with the nervous and respiratory system. It seems, however, more probable that the luminosity is a direct product of the nervous tissue itself. The light consists of a continuous spectrum from C to near H, and is particularly rich in blue and green rays. In the same sub-order also we have the fire-flies, which render the foliage and air of Southern climates so brilliant at night. In the [109] fire-flies, however, both sexes possess wings and in them the male differs from the female Lampyris in being more instead of less luminous than the female. In common with the glow-worm their luminous organ is placed near the caudal end of the abdomen. The light emitted by the fire-flies when examined by the spectroscope and bolometer is found to be devoid of red and infra-red rays but rich in blue and green rays, and is therefore, since it contains only luminous rays, a very economical form of light. The Pyrophorus noctilucus or fire-fly of Mexico and the West Indies in some cases emits two different coloured lights from its body.
Other examples of luminous phenomena in connection with nervous tissues are to be observed in the light which proceeds from the eyes of some animals and insects, especially when seen in darkness. In the case of some moths the light emitted is distinctly violet, cats and dogs give out green, whereas the light from the human eye is orange or red.
We have now traced the history of animal electricity and animal magnetism or its equivalent (?) nervous energy, from the period of its early investigation up to the present time. In the case of the former we have seen as the results of Galvani's, Walsh's, and Ingenhaus' researches that its presence and coincidence with electricity is an established fact, but in the case of the latter we are by no means so sure that nerve force coincides with magnetism. However, whatever this nerve energy may be which led the early philosophers to call it "animal magnetism." it is quite evident that subsequent research and experiment have only tended to amplify the points of analogy. In fact the points of resemblance between nervous energy and ordinary magnetic force are so striking that if these two forms of energy do not actually coincide, there seems good reason, I think, for believing that they are very closely allied. We [110] will therefore summarise these various points of coincidence. They are as follows:
1. Nervous energy when brought into relation with animal electricity results in electro-motive force as evidenced in muscular contraction. Note the parallel between this and electromagnetism in causing the motion of the dynamo.
2. The energy of sound and light are seen to be capable of conversion into nerve energy through the mechanism of special receiving organs, the ear and the eye respectively, just as the energy of sound and light has physically been converted through the mechanism of the telephone and electroscope into electricity and back again into sound and light.
3. Nervous energy appears, as in the case of magnetism, to have the power of attraction. This has been demonstrated by Dr. Paul Joire's experiments with the sthenometer in which the needle is seen to be drawn in the direction of the nerve force. The phenomena of table-turning may also be an example of the concentrated power of this force.
4. Nervous energy like magnetism has been shown to be capable of transference to certain objects and not to others. This had been suspected if not absolutely proved long ago by the evidence of sensitives, but it is only recently, thanks to Dr. Joire, that it has been mechanically demonstrated by his experiments with the sthenometer (vide supra).
5. The conduction of nervous energy has been proved to be slow as compared with electricity.
6. Radiations under the name of N-rays have been demonstrated by Professor Blondlot to be emitted from nervous tissues, and in especially large quantities during functioning. These radiations are believed to consist of at least four groups of ether vibrations, but whether they constitute the whole of the radiations representing nervous [111] energy is not known. They are of long-wave length and are near electro-magnetic waves in point of frequency.
7. These radiations from nerves and nerve centres are capable of reflection, refraction and polarisation, and are in fact forms of radiant energy, and behave in this respect like electro-magnetic, electric, heat and luminiferous radiations.
8. There is good reason for believing that nervous energy is capable of acting over a distance. This is proved by the phenomena of telepathy and thought-transference, in which one brain acts as a transmitter, and the other as a receiver. There are well-authenticated cases of this power of communication occurring over several thousand miles of space, and so well established is the proof that it is now generally admitted by men of science. In this again the analogy between human radiations and telepathy on the one hand and Hertz's electro-magnetic waves and wireless telegraphy on the other is very striking.
9. Luminosity. Although, as said before, this has not been proved to satisfaction with regard to human radiations, there seems reason to believe, apart from Reichenbach's experiments on sensitives, that they may be faintly luminous, though not sufficiently so for ordinary vision to perceive. This is supported by the increased phosphorescence of the platino-cyanide of the barium screen and the action on the photographic plate, and also by the fact that nervous tissues in some of the lower forms of life emit luminous radiations: the glow-worms. fire-flies, etc. Certain magnetic phenomena are also attended with luminosity, such as the glow in Crookes' tubes in the production of X-rays, and the Aurora Borealis.
Before bringing this paper to a close I would make two suggestions — firstly, regarding the action of nervous energy in causing muscular action, and secondly, with reference to a possible explanation of the physical cause of nervous luminous phenomena.
Physical science teaches us that there are ether waves of great wave-length, as compared with those of light and electricity, called electro-magnetic waves, and that if a galvanic current moving through a conductor is placed in a magnetic field, electro-motive force is developed in it, which results in the motion of the conductor if it is free to move. Now we know that muscular tissue has the power of generating galvanic currents, and that in the case of electric eels and torpedo fish this tissue can be so modified that it has the power of accumulating electricity in large quantities. May it not be possible that, on somewhat similar conditions, the nerve cells in the cortex cerebri may have the power of generating waves similar in property to electro-magnetic waves (N-rays?) which, during innervation, are carried by the nerve fibres to the muscles, and thereby producing a magnetic field, give rise in them to the electro-motive force as evidenced by muscular contraction?
With reference to the latter — the nature of nervous luminous phenomena — I would suggest that the emission of light by nerve tissues is a form of fluorescence, and that Reichenbach was probably right when he compared its production to luminous magnetic phenomena, such as the Aurora Borealis, which I think is also a condition of fluorescence.
Before proceeding any further, it will be as well to illustrate by a few experiments what fluorescence is, in the ordinary acceptance of the word. and to remind the reader of the theory of its causation. "If a solution of chlorophyll (the green colouring matter of plants) is placed in a dark room, and a beam of white light allowed to fall upon it, the portions of the solution on which the light first falls becomes luminous and emits a red light." (Watson.)
In this experiment we see that the green radiations of the chlorophyll under the influence of solar radiations are converted back into red radiations, a change, in fact, from [113] radiations of higher frequency and shorter wave-length, to those of lower frequency and longer wave-length. If you take a solution of quinine and hold it up against a beam of sunlight, no apparent change is to be observed in the light after it has traversed the solution. Its intensity does not seem in any measure to be diminished. It will be seen, however, that a bluish light is proceeding from the solution. If we now examine spectroscopically the beam of sunlight after it has passed through the quinine solution, it will be found that it has been almost entirely deprived of its ultra-violet rays, in other words, quinine has converted these invisible rays of high frequency and short wave-length into luminous violet and blue rays of lower frequency and longer wave-length. Now take a solution of quinine and move it along a spectrum in a darkened room, and it will be found that it looks red when held in the red, yellow in the yellow, green in the green, but as soon as it is held in the blue and violet portions, a marked change takes place, and it begins to exhibit a blue light, as it did in the former experiment. This colour increases towards the violet end of the spectrum, and is visible even when the test-tube containing the quinine solution is held beyond the visible spectrum in the ultra-violet portion, in other words, it reinforces the blue and violet light and converts the ultra-violet rays into blue and violet rays.
This phenomenon of absorbing ether radiations of certain wave-lengths, whether luminous or otherwise, and converting them into luminous radiations of greater wave-length and lesser frequency, is called fluorescence. There are many other bodies besides quinine which possess this power, such as paraffin oil, resin, fluor-spar, platino-cyanide of barium, etc. The light emitted by these substances is not monochromic, but contains the light of various colours, the wave-lengths of which, however, are always greater than the wave-lengths of the radiations which cause the fluorescence.
It will be seen that the above are examples of radiations, one of which is within the luminous scale, being acted on from without by another of higher frequency above the luminous scale, namely, the ultra-violet. I would now ask is it possible that radiations of a wave-length so long and low in frequency as to be below the luminous scale can be acted on by radiations of short wave-length and high frequency such as ultra-violet or X-rays, above the luminous scale, with the result that luminous radiations are created and given forth? I would suggest that such a condition of fluorescence is illustrated by the luminosity which takes place in a Crookes' tube in the production of X-rays, also in Lemstroem's experiment, and in the natural phenomenon of the Aurora Borealis, and lastly in luminous nerve phenomena. We know that if a Crookes' tube is gradually exhausted, whilst an electric discharge is caused to pass through the rarefied air, the latter becomes luminous for a while, and as the exhaustion proceeds it ceases to be so, at which point the glass itself of the tube gives out an apple-green fluorescent light. It would appear that the diminished pressure may be favourable to ionic dissociation of the air and glass molecules and whilst in this condition they have conferred on them, owing to the passage of electro-magnetic waves, the vibrations which constitute light. M. Lemstroem's experiment, a tube containing highly rarefied air, caused by exhaustion, is connected by one end with the earth, whilst the other is directed towards the brass ball of an electric machine. If the electric machine is now worked the air in the exhausted tube will be found to emit light. It would appear that the waves of low frequency of the earth's magnetism meeting electric waves of high frequency given out by the electric machine, confer on the unstable molecules of rarefied air the electro-magnetic variations which result in their fluorescence.
In the case of the Aurora Borealis it is believed that [115] electric cathode rays of high frequency are constantly being given out by the sun, especially when sunspots are numerous, and that these on coming under the influence of the earth's magnetic attraction are drawn down by it, so that when they strike the upper rarefied atmosphere at a height of from 100 to 300 miles, they cause it to give out luminous radiations, in other words to become incandescent or fluorescent. It is in fact Lemstroem's experiment produced by natural phenomena.
In like manner it seems reasonable, I think, to believe that N radiations, that is radiations of low frequency and near electro-magnetic in the ether scale, may have the power of converting the ultra-violet rays present in our environment into luminous radiations, which become apparent to our ordinary senses if emitted in sufficient concentration for the purpose.
Such a condition I hold might be supplied by the retina of animals, or a special nerve end-organ in the case of the glow-worm and allied insects. It seems feasible that such organs are able to emit N or other radiations similar to electro-magnetic in a concentrated form. The luminosity is naturally most evident when complete darkness has set in. As above noted, it will be remembered that in the case of the glow-worm and fire-fly the luminous radiations are under the control of the insect's will and are influenced by excitement. Charpentier also observed that with volition, and emotional conditions, N radiations are emitted in considerably greater quantities than when these are not acting.
If this emission of light is due to nervous energy it is a reversal of the process which I have discussed elsewhere of light being converted into nervous energy. [2] Ionic dissociation is here taking place, I would suggest, in the life [116] processes of the protoplasmic nerve cells, and in consequence various forms of energy are being manifested, such as N radiations, etc., and emitted in large quantities, which through the interaction of cathode or ultra-violet radiations present in the surrounding ether (or it may be also evolved by the protoplasmic life processes), confer on these dissociated ions the vibrations which constitute light. It is, so it appears to me, an analogous condition to fluorescence, of which the light given out by a solution of quinine and the Aurora-Borealis are kindred phenomena.
Footnotes
- "Odic Phenomena and New Radiations," by Dr. Jules Regnault, THE ANNALS OF PSYCHICAL SCIENCE, March, 1905. <Full-text>
- "Light and the Visual Sense." A Study In Biological Physics. By Henry A. Fotherby, D.P.H. (Camb.). L.R.C.P. Lond., etc. Knowledge and Scientific News, December, 1906.
Originally published in The Annals of Psychic Science 5:26 (Oct-Nov, 1907).
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