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59 59

60

ROFESSOR LE CONTE of the California University has recently published in the North American Review an interesting paper on the Evidence of the Senses, in which he shows that on the one hand the senses often afford most incorrect information while on the other the powers of such scientific instruments as give exact information would be utterly unsuitable substitutes for our less exact senses. Sight tells us that an object is flat when it is round, touch that an object is double when it is single, hearing that sounds come from close by when they really reach us from a great distance; but on the other hand to have eyes with telescopic power, or fingers as sensitive as a chemist's balance, or ears with the sound-gathering qualities of the microphone, would unfit us for the kind of life we have to lead upon this work-a-day world of ours.

I propose now to discuss the question dealt with by Le Conte, with special reference to the liability of our senses to various forms of error. Taste and smell need not here occupy our attention. They are less used than the other senses in scientific research; and so far as the purposes to which they are chiefly directed are concerned they are in the main trustworthy. They may deceive us by presenting as pleasant what is really deleterious, but once experience has determined the qualities and effects of substances having such and such taste or odour, we are not often deceived in identifying those substances thereafter.

The sense of touch is commonly understood as including the sense of heat-effects. But here, as Reid long since pointed out, our division of the senses is unsound. Undoubtedly the sense of touch is entirely distinct from the sense of heat,-though we may be said to feel in both cases. The error probably arose from the circumstance that the same organs seem employed in noting the effects of contact and the effects of heat. I touch a surface to see if it is hard or soft, rough or smooth, just as I touch a surface to see if it is hot or cold: moreover there is no part of the body which is sensible to the effects of con

tact which is not also sensible to the effects of heat and cold. But we recognise a marked difference between the sense of touch when the tip of the tongue is employed for the moment as the organ of touch, and the sense of taste; yet the difference between taste and touch is not more marked than the difference between heat and touch.

Therefore in dealing with errors affecting the evidence given by the sense of touch, I consider only those really relating to the effects of contact, dealing separately with those relating to the effects of heat and cold.

Aristotle long since pointed out how the sense of touch may be deceived when the organs of touch are employed in some unaccustomed manner. It was he who first mentioned, if he did not invent, the experiment of rolling a pea between the tips of the first and second fingers, after the second finger has been crossed over the first. This experiment is instructive as showing how much of the significance of the teachings of our senses may be due to the effect of long-continued training. Every time we touch with the finger-tips an object of known shape, we are in reality teaching our fingers that such and such impressions have such and such a meaning. When two fingers are crossed, the finger-tips receive different impressions from those which they receive in their normal position, and we naturally misinterpret the meaning of the impressions so received. Thus if I touch with my first and second fingers the sides of a space shaped thus the outsides of the fingers come in contact with the curved surface, whereas the insides of the fingers feel such a surface as this,

,

so soon as the fingers are crossed these effects are reversed; the outsides of the fingers are brought together by the crossing and touch a surface shaped thus telling us apparently that it is really a surface shaped thus that we are touching. To test this apply the crossed fingers to a surface shaped so that the fingers touch the convex curves near their place of meeting now we find that we no longer seem to be touching two curves, but one. It must be admitted, however, that this experiment is less striking than the other; the information conveyed by the finger-tips instead of seeming definitely and decidedly incorrect, appears but vaguely erroneous.

:

Let us try a few other experiments with crossed fingers. Take a penholder or pencil, and with first and second fingers crossed slide the finger-tips along the pencil or holder. If the eyes are closed the fingers seem to tell us emphatically that we are feeling two parallel rods. Yet if the eyes are directed to the fingertips the illusion disappears. This is not, however, because the eyes assure us that there is but one pen or pencil; it is because the eyes show us that the fingers are crossed. To show that mere knowledge will not save us from the illusion, feel with the crossed fingers the tip of the nose. We know certainly that we have but a single nose-tip; yet the absurd and illusory feeling that we have two noses is immediately produced. illusion is strengthened if the crossed finger-tips are caused to slide along the ridge of the nose. Very curious illusions are produced if the crossed fingertips are carried along either lip, or between the lips, or along the bone ridge below either eye or along the ridge above the eye, or round the ear, and so forth. But in my own case, the oddest illusion of all is obtained by crossing the forefinger behind the little finger, (both being bent somewhat towards the palm, so that the second or third fingers are behind them) and then feeling with these crossed fingers the

The

tip of the nose: for now, not only does the nose appear double, but one nose appears to be longer than the other. One can easily understand why this is. Under ordinary conditions the first and little fingers cannot at the same moment feel two bodies which are equidistant from the observer,- -or let us say from the palm. If for instance we place the forefinger tip on the end of a white note on the piano, the little finger tip can only rest on the end of another white note by bending the hand: we can however touch an end of a black note with the forefinger tip while the third finger tip touches the end of a black note, without bending the hand. The lesson taught, then, by constant experience (unnoticed through its very familiarity) is that two bodies so felt extend to different distances. But in the experiment with crossed forefinger and little finger, the finger-tips touch at the same moment the same nose-tip: which appears double because touched by the outside edges of the fingers, and the two noses appear of unequal length because it seems as though the little finger touched one while the forefinger touches the other, each of them at the tip.

Other singular effects may be produced by crossing the fingers, varying the combinations. If the forefinger and second finger of the left hand be crossed as well as those of the right, and a small object be held between the crossed pair of each hand, the most incorrect ideas of the shape of the object are given. I have just tried the experiment for instance on a small box of pen-nibs, holding two opposite corners, one between the crossed finger-tips of the right hand the other between those of the left hand; it was impossible to realise that the object thus held had any regularity of shape at all.

Another experiment on the sense of touch depends on the circumstance that usually the outsides of the hands are so placed that if both touch two surfaces at the same time those surfaces are not in the same direction. Of course the two hands can be placed side by side with their backs uppermost and a flat surface may so touch both; but usually the palms are towards each other, and this is especially the case when both hands are used in holding anything. Place the hands together palm to palm, then cross the arms so that the hands are back to back; if now a book is held between the backs of the hands its edge appears bent. The force of this illusion is different with different persons; but let not those who are not affected by it rejoice as being less easily deceived than their fellows; for, as Sir David Brewster remarks in speaking of an illusion affecting sight, it often happens that the most observant are those most completely deceived by such illusions.

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There is another curious illusion of touch which appears to depend on the teaching which the hands and arms have had (unconsciously) in estimating the dimensions of bodies held in the normal way, in front of the body. Suppose a book lying on a table before the back of the book being towards the right. Take hold of it by the nearest right-hand corner (that is, holding it by the end of the back nearest to you) and pass it over the right shoulder so that the face which had been uppermost lies against the back of the right shoulder in a nearly vertical position. Now pass the left hand round behind under the left shoulder-blade till you can grasp with it the edges of the leaves. You will now find that though you know from the feel of the edges that your left hand holds a side several inches from the back held by the right hand, that side of the book appears to be a continuation of the back of the book,far as direction is concerned. The explanation appears to be simply this: When an object

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you

like a book is held in front of the chest, the right hand holding one side, the left hand reaches the opposite side without effort or stretching; while with a slight amount of stretching the side held by the right hand can be reached now when the book is held behind the back in the way described above, an effort is required to reach with the left hand the side opposite that held by the right, hence the same effect is produced on the mind as when in the normal way of holding objects of the kind the left hand is stretched over to the right hand's side of the object; thus instead of the left hand touching the side opposite that held by the right, it appears to touch the same side.

So much for illusions affecting touch. Or rather, these afford sufficient evidence that the sense of touch may be readily deceived. But in reality, scarcely a day passes without our noticing, if we are at all observant, illusions affecting this sense. If we observe the circumstances under which such illusions occur we generally find that they arise when some organ of touch is used in a novel or unusual way. But in the majority of cases arising in ordinary life the sense of touch acts in combination with either the sense of sight or the sense of hearing, and consequently the illusions arising are not such simple examples of errors in the evidence afforded by the sense of touch as those considered above. (To be continued.)

LP

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ET us now turn to another phase of the question, and see how far that deviates from credibility, or accords with the experience of our common life. Dwelling, apparently with much complacency, on what he calls the Horrendus Maximini interritus-alias the painful death of the tyrant Maximinus-Lactantius says (De Mortibus Persecutorum) :-"Deinde post multos gravesque cruciatus, cum caput suum parietibus infligeret, exilierunt oculi ejus de caveis ; and it is worth while asking whether any one, sane or otherwise, can per "dash out his own brains," or cause his own eyes to start or jump out of their sockets. Grave writers and "able editors,' as Carlyle would call them, say the thing is possible, and we occasionally read of such performances in connection with police-cells, lunatic asylums, and the like. Thus the reverend author of a little book called "A Popular History of the Insurrection of 1798," after mentioning the dreadful sufferings that were endured by those who were subjected to the horrors of half-hanging and the pitch-cap in that year, says, p. 72, that the victims of these pleasantries "dashed their brains out, in the madness of intolerable pain, against some neighbouring wall, and thus put an end at once to their life and misery"; and the following occurs in Mr. O'Hagan's translation of the Song of Rowland":

He (R.) saw the Saracen seize his sword,
His eyes he ope'd and he spoke one word-

On the golden crest he smote him full,
Shattering steel and bone and skull;
Forth from his head his eyes he beat,
And cast him lifeless before his feet,*

where we may safely leave him for the present.

* Somewhat akin to this is the crime or occurrence mentioned in

If now, making every allowance for the poetic licence assumed above, as well as for the strange juxtaposition of bone and skull, as if they were not here as elsewhere identical, we come to the beating out of the eyes and the dashing out of the brains, and ask ourselves if such things ever can or ever do happen, our answer will be that they probably never do. And yet stranger occurrences than even these have been gravely recorded by eminent historians. As an instance in point, we will quote the following from Milman. Mentioning the hard usage according to which the Syndic of the Jews was obliged to salute the Mayor of Toulouse about the year 980, he says (ut supra, vol. ii., p. 146) that: "A stern, iron-handed magistrate struck the poor Syndic with such force as to scatter the brains of the unfortunate unbeliever "--and the hand that achieved this feat must, indeed, have been made of iron or other equally potent material; for unless this wretched Syndic was suffering from that very rare condition called Mollities ossium, or that our magistrate had the strength of a Hercules, it is hard to conceive how such a result could follow from such a cause. And yet there is no affectation of poetic licence or unreality here-the possibility of the thing is taken for granted, and there is no such qualification as even a query or a note of admiration could supply. All we need, therefore, say in this connection here, is that where grave and learned writers like Milman put forward such statements without question, we ought not to be surprised when we find Scott and other romancists of his class investing their heroes with such attributes as are clearly beyond the reach of ordinary mortals.

It is, we believe, generally admitted that negroes have sometimes succeeded in committing suicide by swallowing their tongues; in other words, by doubling them back, and then drawing them into their throat, so as to stop the access of air to the lungs;* and excision of the tongue is now a recognised surgical operation. But this operation to be successful or effective must be performed by a skilled surgeon or a trained executioner, and persons desirous of shuffling off the mortal coil never dream of trying to do so through the medium of this organ. We have it, however, on the authority of Major Macpherson ("Memorials of Service in India," p. 67) that, "a Khond, captured by our troops in Baramootah, immediately tore out his tongue by the roots and died," probably of the hæmorrhage which such an attempt would necessarily entail. But it does not seem possible for any

the following lines from the old song, see Roberts' Legendary Ballads :

"The Clerks of Owsenford,"

"Then he has ta'en the twa bonny clerks,
Bound them frae tap to tae,

Till the reddest blude in a' their veins
Out oure their nails did gae."

The following story from Gilbert's "History of the Viceroys of Ireland," page 63, would, if true, seem to justify the accounts given by Scott and others of their fabled heroes. Describing a fend that existed between Hugues de Lasci, "John's representative, and a powerful baron named De Curci," our author says that the latter was attacked by the former while at prayers in the cathedral of Down, with the following result: "With the pole of a cross snatched from the head of a grave in the churchyard, De Curci slew thirteen of De Lasci's soldiers ere he was overpowered and sent in fetters to the Tower of London."-Credat Judæus Apella, non ego!

* Woodman and Tidy's "Handybook of Forensic Medicine," p. 956. The following is, perhaps, the most extraordinary case of suicide on record. It is gravely related by Mr. Talboys Wheeler in his able "History of India," Vol. I. p. 323, and runs to the effect that, "Drona, one of the heroes of the Mahábhárata, believing that his son was dead, drew up all the breath of his body into a spot in the neighbourhood of his heart and drove it into his head, upon which the top of his skull was burst open, and his soul escaped through the orifice like a ray of the sun."

one to tear out his own tongue with his own unaided hands, and in proof of this we have only to ask our readers to try and seize that somewhat slippery muscle themselves. If they will try they will probably find that they cannot introduce the hand into the mouth without producing sensations that would prove fatal to such an attempt; and, even supposing that they had so far succeeded, how are they to drag-for that's the assumption this very elastic piece of mechanism from its strong and deep-rooted attachments? The thing seems to be impossible, and we need not fear that our allusion to it will induce any future felo-de-se to prefer it to the easier and speedier alternatives of a jump over London-bridge or a resort to the ever-ready razor.

He

But we must hurry on to a close, and with this view restrict ourselves to one or more illustrative extracts of the character here contemplated. Describing the decisive battle that took place between the forces of Mahomed Shah Adily and those of the famous Akbur, Major Briggs says "Rise of the Mahomedan Power in India," that the former's Commander-in-Chief, one Hemoo, was pierced in the eye with an arrow, which penetrated the brain; "he sunk into his howda from extreme agony, and the greater part of his troops, fearing that his wound was mortal, left him. Raising himself again, Hemoo drew the arrow from his head, and with it the eye from its socket, which he wrapt up in his handkerchief. continued to fight with unabated vigour until he contrived, with the few men who remained faithful to him, to force his way through the enemy's line." That a brave man should continue to fight for dear life after he had lost an eye, in battle or otherwise, is no very uncommon or extraordinary thing; but that he should do so under the circumstances here disclosed is certainly unusual, and if such wounds as are casually inflicted in this region by the poke of an umbrella-handle or the thrust of a walking-stick prove, as we believe they always do, fatal, we may well doubt the practicability of the feat narrated above.

A writer in the "Philosophical Transactions" (A New Abridgment, vol. iv., pp. 106-7) gives such an account of the effects of a cancer on the brain of a certain person as, if verifiable, would go far to show that Shakespeare's belief, "the man is dead when the brains are out," admits of some qualification. This account may, for brevity's sake, be summarised as follows:-A certain man "had a cancer which spread itself, in spite of the endeavours of the most eminent surgeons of the day, over all the cheek, into his mouth, and across the upper part of his nose, where it perforated the bone and ate away all the flesh round his eye, so that he could take out the latter with his own hands," and we suppose, though this is not actually said, put it into his pocket. It finally exposed the dura mater, and with it the brain itself to view, several portions of which came away. "And what was most extraordinary was that he perfectly retained his senses, and rose every day to dress the ulcer himself till a considerable quantity of the brain had come away." When he died, four days after taking to his bed for the last time, "his brain was totally consumed, and nothing remained in the cranium but a small quantity of black putrid matter," and we are gravely asked by this philosophical writer to believe this.

Were we to do so, we would be simply flying in the teeth of all experience, and reducing the researches. and the observations of our best scientists to a level with the wild exaggerations of Mr. Holloway or St. John Long. This we decline to do, and if a man may go about his ordinary business without any