Part 6

The old hypothesis of the influence of a magnet on the human body was at this time revived, and Charcot’s pupils found that when a susceptible female patient held in the hand a bar of iron surrounded by a coil of copper wire leading to a chemical electric cell or battery nothing happened so long as the connection was broken. But as soon as the wire was connected so as to set up an electric current and to make the bar of iron into a magnet, the hand and arm (up to the shoulder) of the young woman holding the bar, lost all sensation. She was not allowed to see her hand and arm, and was apparently quite unconscious of the thrusting of large carpet-needles into, and even through, them, though as long as the bar of iron was not magnetised she shrunk from a pin-prick applied to the same part. I saw this experiment with Charcot and some others present, and I noticed that the order to an assistant to “make contact,” that is to say, to convert the bar of iron into a magnet, was given very emphatically by Charcot, and that there was an attitude of expectation on the part of all present--which was followed by the demonstration by means of needle-pricking that the young woman’s arm had lost sensation, or, as they say, “was in a state of anæsthesia.”

Charcot went away saying he should repeat the experiment before some medical friends in an hour or two. In the meantime, being left alone in the laboratory with my companion as witness, I emptied the chemical fluid (potassium bichromate) from the electric battery and substituted pure water. It was now incapable of setting up an electric current and converting the bar into a magnet. When Charcot returned with his visitors, the patient was brought in, and the whole ritual repeated. There was no effect on sensation when the bar was held in the hand so long as the order to set the current going, and so magnetise the bar, had not been given. At last the word was given, “Make!” and at once the patient’s arm became anæsthetised, as earlier in the day. We ran large carpet-needles into the hand without the smallest evidence of the patient’s knowledge. The order was given to break the current (that is, to cease magnetising the bar), and at once the young woman exhibited signs of discomfort, and remonstrated with Charcot for allowing such big needles to be thrust into her hand when she was devoid of sensation! My experiment had succeeded perfectly.

It would not have done to let Charcot, or anyone else (except my witness) know that when the order “Make” was given, there was no “making,” but that the bar remained as before un-magnetised. The conviction of everyone, including Charcot himself, that the bar became a magnet, and that loss of sensation would follow, was a necessary condition of the “suggestion” or control of the patient. It was thus demonstrated that the state of the iron bar as magnet or not magnet had nothing to do with the result, but that the important thing was that the patient should believe that the bar became a magnet, and that she should be influenced by her expectation, and that of all those around her, that the bar, being now a magnet, sensation would disappear from her arm. With appropriate apologies I explained to Charcot that the electric battery had been emptied by me, and that no current had been produced. The assistants rushed to verify the fact, and I was expecting that I should be frigidly requested to take my leave, when my hand was grasped, and my shoulder held by the great physician, who said, “Mais que vous avez bien fait, mon cher Monsieur!” I had many delightful hours with him in after years, both at the Salpêtrière and in his beautiful old house and garden in the Boulevard St. Germain.

There are few “subjects” in this country for the student of hypnotism to equal the patients of the Salpêtrière and other hospitals in France--and very few amongst those who read, and even write, about “occultism” and “super-normal phenomena” know the leading facts which have been established in regard to this important branch of psychology. The study of the natural history of the mind, its modes of activity, and its defects and diseases is of fundamental importance--but its results are often either unknown or greatly misunderstood by those who have most need of such knowledge, namely those who, mistaking the attitude of an ignorant child for that of “a candid inquirer,” try to form a judgment as to the truth or untruth of stories of ghosts, thought-transference, spirit-controls, crystal-gazing, divining-rods, amulets, and the evil eye.

27. _Luminous Owls and Other Luminous Animals and Plants_

A correspondent lately described in a letter to a London newspaper what he believed to have been “a luminous owl,” which was seen flying about at night in Norfolk. He mentioned the well-known fact that the dense greasy patch of feathers on the breast of the heron is said to be luminous by many trustworthy observers. It is very probable that it was some carnivorous or fish-eating bird, which was thus seen in a luminous condition at night. The occurrence is much more in accordance with known facts than most people would suppose to be the case. Light, even strong light, is produced by many natural objects without the accompaniment of heat. We usually expect not merely fire where there is smoke, but heat--in fact, great heat, where there is light or flame. Yet there are many instances to the contrary, and the word “phosphorescence” is used to indicate a production of light without heat in reference to the fact that phosphorus is luminous, even when covered with water, although no appreciable heat accompanies the light such as we are accustomed to observe in ordinary “combustion” or burning.

There is more than one kind of phosphorescence. We separate the phosphorescence which is due to the oxidation of peculiar fatty matters in the bodies of plants and of animals (such as glow-worms) from that which is caused by the breaking or heating of crystals (white arsenic and apatite), or by longer or shorter exposure to the sun’s rays (luminous paint), or by radio-activity, or by electrical discharges in vacuum tubes.

The “luminous owl” of the above-mentioned correspondent and the luminous breast of the heron probably owe their strange appearance to the birds having smeared themselves with phosphorescent carrion or dead fish, the luminosity of which is due to bacteria. The simplest case of phosphorescence in living things is that of the almost ubiquitous phosphorescent bacteria, minute microbes like those which cause putrefaction. They can be obtained and cultivated from almost any sample of sea water. A thin slice of meat placed in a shallow dish of salt water, so as to be barely covered by the liquid, will in cool, damp weather, almost certainly become covered with the growth of this phosphorescent germ and appear brilliantly luminous. The populations of seaside towns have often been terrified by all the meat in the butchers’ shops suddenly becoming thus phosphorescent. The growth may be cultivated in flasks of salt broth. I have prepared such flasks, which, when shaken so as to introduce oxygen, give out a heatless blaze of light of a greenish colour, brilliant enough to light up a room. I once found a bone in a dog’s kennel which was brilliantly phosphorescent owing to this bacterium. I kept it for several days and showed it to Huxley as well as to other friends. A certain kind of phosphorescent bacteria are parasitic in the blood of sandhoppers, causing a disease which kills them. The diseased sandhoppers shine like glow-worms. I have found them abundantly on the sea shore near Boulogne and near Trouville, but not yet on the English coast. The bacteria can be seen with the microscope and inoculated from diseased luminous sandhoppers into healthy ones by using a needle to prick first the diseased and then the healthy creature.

The animals of the sea are often provided with secreting organs, producing a fatty body which can be oxidised and made luminous at the pleasure of the animal. Thus many marine worms and minute sea-shrimps give out brilliant flashes of light. Jelly-fish of many kinds, and the minute noctiluca, no bigger than a pin’s head, and the three-horned animalcule Ceratium tripos are the usual cause of the phosphorescence of the sea on our own coast. Deep-sea fishes are provided with large phosphorescent discs or plates on the surface of the body, which are sometimes furnished with lenses like a bull’s-eye lantern. Glow-worms and fire-flies and some tropical beetles are examples of insects which have fatty phosphorescent organs which they can illuminate (oxidise) at pleasure, under the control of the nervous system. Some of the West Indian phosphorescent beetles are remarkable for having “lights” of two different colours. In the marshes around Mantua the fire-flies are so abundant at the end of June that the air for miles is full of them, and the sight so extraordinary and beautiful as to be worth a long journey to see. I have seen fire-flies as far north as Bonn on the Rhine. Once I was nearly upset by a horse shying at a glow-worm on a bank in Worcestershire. Some moulds and well-grown toadstools are phosphorescent, and a phosphorescent earthworm, a peculiar species, now well known, was first of all discovered in the South of Ireland by the late Professor Allman. In the autumn I have often picked up the phosphorescent centipede, which is remarkable for the fact that the phosphorescent material is a kind of slime which exudes from the body--the creature leaving thus a luminous trail behind it as it crawls. The piddock, or pholas--a boring sort of mussel--has brilliant phosphorescent glands, and the boys at Naples love to munch these shell-fish at night, and then to alarm the passer-by by opening their mouths, and showing a brilliant green light within. Cases are recorded, but not recently, of persons suffering from tuberculosis becoming phosphorescent; a possible, but certainly a rare, occurrence. Animal and vegetable phosphorescence is varied in colour. The light emitted is blue-green, green, yellow, orange, and even red in different cases. It is always due to the oxidation of a separate fatty chemical body, which can in many instances be extracted, then dried, and subsequently made luminous by moistening with ether, in consequence of which oxidation by the oxygen of the atmosphere is facilitated.

28. _Reminiscences of Lord Kelvin_

The late Lord Kelvin was one of the most fascinating personalities in the learned world. He uttered with a delightful simplicity the thoughts, however romantic and fanciful, which bubbled up in his wonderful brain. It was because he was so much of a poet that he was so great a man of science. Atoms and molecules and vortices, and the vibrations and gyrations of ether, and “sorting demons” were all pictured in his mind’s eye, and used as counters of thought to give shape and the equivalent of tangible reality to his conceptions. By such conceptions he was able to present to himself and his listeners the complex mechanisms of crystals, of liquids, of gases, of electrical and magnetic currents, and the endless astounding proceedings of rays of light unsuspected by the ordinary man.

I think the last occasion on which he spoke in public was after Sir David Gill’s brilliant address to the British Association at Leicester last August. Lord Kelvin was sitting close to me on that occasion, and I noticed that he never moved his gaze from the speaker. He followed Sir David’s account of stars, whose distance is stated by the number of years it takes for their light to travel to this earth, like an enraptured schoolboy, and cheered when the evidence for the existence of two great streams of movement of the heavenly bodies, in opposite directions, going no one knows whither, coming no one knows whence, was sketched to us by the lecturer. In proposing a vote of thanks to Sir David Gill, Lord Kelvin burst into a sort of rhapsody, in which, with unaffected enthusiasm, he declared that we had been taken on a journey far more wonderful than that of Aladdin on the enchanted carpet; we had been carried to the remotest stars and well-nigh round the universe, and brought back safely to Leicester on the wings of science, and the most marvellous thing about it all was that it is true!

A few weeks before this Lord Kelvin was at the dinner in celebration of the jubilee of the foundation of the Chemical Society. In the speech which he then made he referred to the painful accident of a year or so ago which we had all so much regretted, when he had burnt his hand accidentally in some experiments with phosphorus, and had had to carry his arm in a sling for some weeks. “Lord Rayleigh, the president of the Royal Society,” he said, “has just told us how, as a boy, he gave proof of his devotion to chemical science by burning his fingers with phosphorus--but I think my devotion must be considered greater than his, for I burnt my fingers very badly with phosphorus only last year, when I was 83 years old. It was at the end of April. My friends said I was old enough to know better, and it should have happened, not at the end of April, but on the first day, of that month.” Lord Kelvin was associated in work in the sixties and seventies with another splendid man, Tait, of Edinburgh, who, besides being a great professor of “Natural Philosophy,” and joint author of the celebrated treatise known as _Thomson and Tait_, was a great athlete--a golfer of the first class, a first-rate billiard player, and a wise lover of good ale, which he drank and gave to his friends to drink, whilst he discoursed as few, if any, to my knowledge, can now do, of things philosophical, mathematical, and humane.

29. _The So-called Jargon of Science_

It is often discussed as to whether science fails to obtain the attention of the public and to excite intelligent interest, owing to the obscure language which lecturers and writers use when attempting to expound scientific views and discoveries to “the ordinary man,” or whether the fault lies with the “ordinary man” himself, who is too frivolous to bother about following carefully the words addressed to him, and, moreover, has never learnt even the A B C of science at school. It is certainly the case, as Professor Turner, the Oxford professor of astronomy, has pointed out, that a popular lecturer could tell his auditors a good deal more in an hour if they already had the elements of his subject at their fingers’ ends than he can under the existing state of neglect of school education in the natural sciences. That, however, seems to be obvious enough, and does not touch the real question.

I have had a long experience, both in lecturing myself and in assisting in the training of others to lecture and also to inform the uninstructed public by means of museum-labels and popular notes. It seems to me that there are a large number of men who, even though capable of expressing themselves clearly under usual circumstances, yet fail to do so when trying to expound or to teach, in consequence of three distinct faults, any one of which is enough to render their discourse or writing hopelessly obscure to “the man in the street.” These are, first, a kind of pride in using special terms and modes of expression which infatuates the lecturer or writer, and leads him, without reflection, to an attitude of mind expressed by saying, “That is the correct statement about this matter, short and true. If you don’t understand it, there are others who can. You can leave it alone; it is not worth my while to spend time and trouble to explain further; it is for you to give yourselves the trouble to find out what I mean.” The second fault is a real incapacity (which occurs in many learned men) to realise the state of mind of the uninstructed man, woman or child who eagerly desires to be instructed: this is want of imagination and want of sympathy. There is no cure for those who fail as teachers for either of these two reasons.

The third fault is much more widely at work, and the most kindly sympathetic lecturers and writers--but more especially lecturers--often suffer from it and could easily amend their practice. It consists in the attempt to tell the audience or reader too much--vastly too much--in the limit of one hour, or within the space of a few lines or pages. This failure is well-nigh universal. I have heard a distinguished discoverer, an eloquent and able man, try to tell a completely ignorant audience in one hour the results of years of experiment and work by many men on the electrical currents observed in nerves. The audience did not know what is meant by an electrical current, nor anything about nerves, nor a single one of the technical terms necessarily used by the lecturer. The task was an impossible one. In six lectures it might have been accomplished, and great delight and increase of understanding afforded to the listeners instead of perplexity and a sense of their own incapacity and the hopeless obscurity of science. That, I am convinced, is the real trouble, viz., the attempt to tell too much in a short time, the failure by the lecturer to arrange his exposition in a series of well-considered, definite steps, each exciting the desire to know more, and each given sufficient time and experimental illustration or pictorial demonstration to lodge its meaning and value safely and soundly in the tender brain of the ignorant but willing listener. I am convinced that there is in very many lecturers a tendency to try to crowd and compress into one lecture what should occupy ten--if the willing and intelligent but ignorant listener is to feel happy and is really to understand what is said and done for his instruction. A special difficulty also arises from the fact that the lecturer often feels himself called upon to address and to say something to those among the audience who already know a good deal about his subject, as well as to make things clear to those who are absolute novices.

Some people have made this discussion the opportunity for attacking on the one hand the English language, and on the other the use of special names applied by men of science to special things and special processes. We cannot at once change the English language, even did we wish to do so. But the creation of special names to distinguish things not distinguished from one another in common speech is a necessity. It cannot be avoided. It is mere impatience and temper to call the names and terms which are necessary as counters of thought “jargon.” No doubt there may be in some lecturers and writers a tendency to excessive use of special terms and names, but the real trouble in the matter arises from the too rapid thrusting of a large number of such unfamiliar words upon an untrained audience. If new words are introduced in moderation they can be assimilated. They cannot be dispensed with altogether. A correspondent lately complained to me that I wrote of the minute creature which causes the sleeping sickness as a Trypanosome, whereas, had I called it “a blood-parasite” he would have known what I meant, and been able to follow my statement more easily. I am sorry to say that I cannot agree with him. There are many kinds of blood-parasites; there are the worms known as Filariæ, there are the vegetable microbes known as bacteria and bacilli and spirilla, and there are minute creatures of an animal nature called pyroplasma and trypanosoma (beside some others). These must be distinguished from one another if we are to understand anything about the causation of disease by microbes. It would be mere muddling and confusion to simply call them all by the same name, simply “blood parasite.” That would cause the same sort of confusion as would occur if the Smiths or Browns of our acquaintance had no Christian names by which we can separate each member of the class from the others and assign to him his own special qualities, opinions, and property. What some people call “scientific jargon” is assuredly not a thing to be proud of or to mouth with a sense of superiority. Nevertheless, it is absolutely necessary, and must be introduced gently and considerately to the stranger who can and will, if reasonably handled, appreciate the immeasurable advantage of having distinct words to signify distinct things. That, after all, is an elementary feature in all language. And just as the “jargon” of a game, a sport, or a profession has a fascination for those who use it, and forms a bond of union or special understanding between them, so inevitably does the jargon of a branch of science flourish in the thought and on the lips of those who devote themselves to that branch, and bind them in a sort of freemasonry. We do not expect cricketers or golfers to talk in plain English; why should we expect chemists or naturalists to do so? After all, it is a question of moderation and of gradually increasing the dose. The beginner must not be terrified by an array of outlandish words.

30. _Rats and the Plague_

Rats! Who said rats? That is an important question, because the word means different things to different people. To some persons “rats” means simply “nonsense”! To Sir James Crichton Browne it means the devastator of stores and the dread carrier of bubonic plague. To the naturalist it means a group or natural cohort of small mammals similar to our common rat and mouse, representatives of which are found in every quarter of the globe and in almost every island of the sea. The distinct “kinds” or “species” are numbered by the hundred. They are extraordinarily alike, and can only be distinguished and classified into proper “species” by careful examination and measurement. Mr. Oldfield Thomas, of the Natural History Museum, has made a special study of them. To give an idea of his work, it may be mentioned that ninety different names had been given by previous writers to as many apparently distinct kinds of rat occurring in India. But by careful measurement and study of the relations to one another of these rats, Mr. Thomas has reduced the number of really distinct Indian species of rats and mice (for a mouse is only a smaller rat) to nineteen. What we call in English water-rats, or water-voles, field-voles, and such little foreign beasts as the lemming and the hamster, are very close to rats in appearance, but are separated on account of clear differences of structure from true rats and mice.